Infertility noun [ Latin infertilitas : confer French infertilité .] The state or quality of being infertile; unproductiveness; barrenness.

The infertility or noxiousness of the soil.

Sir M. Hale.

Infest adjective [ Latin infestus . See Infest , transitive verb ] Mischievous; hurtful; harassing. [ Obsolete] Spenser.

Infest transitive verb [ imperfect & past participle Infested ; present participle & verbal noun Infesting .] [ Latin infestare , from infestus disturbed, hostile, troublesome; in in, against + the root of defendere : confer French infester . See Defend .] To trouble greatly by numbers or by frequency of presence; to disturb; to annoy; to frequent and molest or harass; as, fleas infest dogs and cats; a sea infested with pirates.

To poison vermin that infest his plants.

Cowper.

These, said the genius, are envy, avarice, superstition, love, with the like cares and passions that infest human life.

Addison.

And the cares, that infest the day,
Shall fold their tents, like the Arabs,
And as silently steal away.

Longfellow.

Infestation noun [ Latin infestatio : confer French infestation .] The act of infesting or state of being infested; molestation; vexation; annoyance. Bacon.

Free from the infestation of enemies.

Donne.

Infester noun One who, or that which, infests.

Infestive adjective [ Latin infestivus . See In- not, and Festive .] Having no mirth; not festive or merry; dull; cheerless; gloomy; forlorn. [ R.]

Infestivity noun Want of festivity, cheerfulness, or mirth; dullness; cheerlessness. [ R.]

Infestuous adjective [ Latin infestus . See Infest , adjective ] Mischievous; harmful; dangerous. [ Obsolete] " Infestuous as serpents." Bacon.

Infeudation noun [ Late Latin infeudatio , from infeudare to enfeoff: confer French inféodation . See Feud a fief.]

1. (Law) The act of putting one in possession of an estate in fee. Sir M. Hale.

2. The granting of tithes to laymen. Blackstone.

Infibulation noun [ Latin infibulare , infibulatum , to clasp, buckle, or button together; prefix in- in + fibula clasp, buckle: confer French infibulation .]

1. The act of clasping, or fastening, as with a buckle or padlock.

2. The act of attaching a ring, clasp, or frame, to the genital organs in such a manner as to prevent copulation.

Infidel adjective [ Latin infidelis ; prefix in- not + fidelis faithful, from fides faith: confer French infidèle . See Fidelity .] Not holding the faith; -- applied esp. to one who does not believe in the inspiration of the Scriptures, and the supernatural origin of Christianity.

The infidel writer is a great enemy to society.

V. Knox.

Infidel noun One who does not believe in the prevailing religious faith; especially, one who does not believe in the divine origin and authority of Christianity; a Mohammedan; a heathen; a freethinker.

» Infidel is used by English writers to translate the equivalent word used Mohammedans in speaking of Christians and other disbelievers in Mohammedanism.

Syn. -- Infidel , Unbeliever , Freethinker , Deist , Atheist , Sceptic , Agnostic . An infidel , in common usage, is one who denies Christianity and the truth of the Scriptures. Some have endeavored to widen the sense of infidel so as to embrace atheism and every form of unbelief; but this use does not generally prevail. A freethinker is now only another name for an infidel . An unbeliever is not necessarily a dis believer or infidel, because he may still be inquiring after evidence to satisfy his mind; the word, however, is more commonly used in the extreme sense. A deist believes in one God and a divine providence, but rejects revelation. An atheist denies the being of God. A sceptic is one whose faith in the credibility of evidence is weakened or destroyed, so that religion, to the same extent, has no practical hold on his mind. An agnostic remains in a state of suspended judgment, neither affirming nor denying the existence of a personal Deity.

Infidelity noun ; plural Infidelities [ Latin infidelitas : confer French infidélité .]

1. Want of faith or belief in some religious system; especially, a want of faith in, or disbelief of, the inspiration of the Scriptures, of the divine origin of Christianity.

There is, indeed, no doubt but that vanity is one of the principal causes of infidelity .

V. Knox.

2. Unfaithfulness to the marriage vow or contract; violation of the marriage covenant by adultery.

3. Breach of trust; unfaithfulness to a charge, or to moral obligation; treachery; deceit; as, the infidelity of a servant. "The infidelity of friends." Sir W. Temple.

Infield transitive verb To inclose, as a field. [ R.]

Infield noun
1. Arable and manured land kept continually under crop; -- distinguished from outfield . [ Scotland] Jamieson.

2. (Baseball) The diamond; -- opposed to outfield . See Diamond , noun , 5.

Infile transitive verb To arrange in a file or rank; to place in order. [ Obsolete] Holland.

Infilm transitive verb To cover with a film; to coat thinly; as, to infilm one metal with another in the process of gilding; to infilm the glass of a mirror. [ R.]

Infilter transitive verb & i. [ imperfect & past participle Infiltered ; present participle & verbal noun Infiltering .] [ Confer Infiltrate .] To filter or sift in.

Infiltrate intransitive verb [ imperfect & past participle Infiltrated ; present participle & verbal noun Infiltrating .] [ Prefix in- + filtrate : confer F, s'infiltrer . Confer Infilter .] To enter by penetrating the pores or interstices of a substance; to filter into or through something.

The water infiltrates through the porous rock.

Addison.

Infiltrate transitive verb To penetrate gradually; -- sometimes used reflexively. J. S. Mill.

Infiltration noun [ Confer French infiltration .]

1. The act or process of infiltrating, as of water into a porous substance, or of a fluid into the cells of an organ or part of the body.

2. The substance which has entered the pores or cavities of a body. Addison.

Calcareous infiltrations filling the cavities.

Kirwan.

Fatty infiltration . (Medicine) See under Fatty . -- Infiltration gallery , a filter gallery.

Infiltrative adjective Of or pertaining to infiltration. Kane.

Infinite adjective [ Latin infinitus : confer French infini . See In- not, and Finite .]

1. Unlimited or boundless, in time or space; as, infinite duration or distance.

Whatever is finite, as finite, will admit of no comparative relation with infinity; for whatever is less than infinite is still infinitely distant from infinity; and lower than infinite distance the lowest or least can not sink.

H. Brooke.

2. Without limit in power, capacity, knowledge, or excellence; boundless; immeasurably or inconceivably great; perfect; as, the infinite wisdom and goodness of God; - - opposed to finite .

Great is our Lord, and of great power; his understanding is infinite .

Ps. cxlvii. 5.

O God, how infinite thou art!

I. Watts.

3. Indefinitely large or extensive; great; vast; immense; gigantic; prodigious.

Infinite riches in a little room.

Marlowe.

Which infinite calamity shall cause
To human life.

Milton.

4. (Math.) Greater than any assignable quantity of the same kind; -- said of certain quantities.

5. (Mus.) Capable of endless repetition; -- said of certain forms of the canon, called also perpetual fugues , so constructed that their ends lead to their beginnings, and the performance may be incessantly repeated. Moore (Encyc. of Music).

Syn. -- Boundless; immeasurable; illimitable; interminable; limitless; unlimited; endless; eternal.

Infinite noun
1. That which is infinite; boundless space or duration; infinity; boundlessness.

Not till the weight is heaved from off the air, and the thunders roll down the horizon, will the serene light of God flow upon us, and the blue infinite embrace us again.

J. Martineau.

2. (Math.) An infinite quantity or magnitude.

3. An infinity; an incalculable or very great number.

Glittering chains, embroidered richly o'er
With infinite of pearls and finest gold.

Fanshawe.

4. The Infinite Being; God; the Almighty.

Infinitely adverb
1. Without bounds or limits; beyond or below assignable limits; as, an infinitely large or infinitely small quantity.

2. Very; exceedingly; vastly; highly; extremely. " Infinitely pleased." Dryden.

Infiniteness noun The state or quality of being infinite; infinity; greatness; immensity. Jer. Taylor.

Infinitesimal adjective [ Confer French infinitésimal , from infinitésime infinitely small, from Latin infinitus . See Infinite , adjective ] Infinitely or indefinitely small; less than any assignable quantity or value; very small.

Infinitesimal calculus , the different and the integral calculus, when developed according to the method used by Leibnitz, who regarded the increments given to variables as infinitesimal.

Infinitesimal noun (Math.) An infinitely small quantity; that which is less than any assignable quantity.

Infinitesimally adverb By infinitesimals; in infinitely small quantities; in an infinitesimal degree.

Infinitival adjective Pertaining to the infinite mood. " Infinitival stems." Fitzed. Hall.

Infinitive noun [ Latin infinitivus : confer French infinitif . See Infinite .] Unlimited; not bounded or restricted; undefined.

Infinitive mood (Gram.) , that form of the verb which merely names the action, and performs the office of a verbal noun. Some grammarians make two forms in English: ( a ) The simple form, as, speak , go , hear , before which to is commonly placed, as, to speak ; to go ; to hear . ( b ) The form of the imperfect participle, called the infinitive in -ing ; as, going is as easy as standing .

With the auxiliary verbs may , can , must , might , could , would , and should , the simple infinitive is expressed without to ; as, you may speak ; they must hear , etc. The infinitive usually omits to with the verbs let , dare , do , bid , make , see , hear , need , etc.; as, let me go ; you dare not tell ; make him work ; hear him talk , etc.

» In Anglo-Saxon, the simple infinitive was not preceded by to (the sign of modern simple infinitive), but it had a dative form (sometimes called the gerundial infinitive) which was preceded by to , and was chiefly employed in expressing purpose. See Gerund , 2.

The gerundial ending (- anne ) not only took the same form as the simple infinitive (- an ), but it was confounded with the present participle in - ende , or - inde (later - inge ).

Infinitive noun (Gram.) An infinitive form of the verb; a verb in the infinitive mood; the infinitive mood.

Infinitive adverb (Gram.) In the manner of an infinitive mood.

Infinito adjective [ Italian ] (Mus.) Infinite; perpetual, as a canon whose end leads back to the beginning. See Infinite , adjective , 5.

Infinitude noun
1. The quality or state of being infinite, or without limits; infiniteness.

2. Infinite extent; unlimited space; immensity; infinity. "I am who fill infinitude ." Milton.

As pleasing to the fancy, as speculations of eternity or infinitude are to the understanding.

Addison.

3. Boundless number; countless multitude. "An infinitude of distinctions." Addison.

Infinituple adjective [ Confer Quadruple .] Multiplied an infinite number of times. [ R.] Wollaston.

Infinity noun ; plural Infinities . [ Latin infinitas ; prefix in- not + finis boundary, limit, end: confer French infinité . See Finite .]

1. Unlimited extent of time, space, or quantity; eternity; boundlessness; immensity. Sir T. More.

There can not be more infinities than one; for one of them would limit the other.

Sir W. Raleigh.

2. Unlimited capacity, energy, excellence, or knowledge; as, the infinity of God and his perfections. Hooker.

3. Endless or indefinite number; great multitude; as an infinity of beauties. Broome.

4. (Math.) A quantity greater than any assignable quantity of the same kind.

» Mathematically considered, infinity is always a limit of a variable quantity, resulting from a particular supposition made upon the varying element which enters it. Davies & Peck (Math. Dict.).

5. (Geom.) That part of a line, or of a plane, or of space, which is infinitely distant. In modern geometry, parallel lines or planes are sometimes treated as lines or planes meeting at infinity.

Circle at infinity , an imaginary circle at infinity, through which, in geometry of three dimensions, every sphere is imagined to pass. -- Circular points at infinity . See under Circular .

Infirm (ĭn*fẽrm") adjective [ Latin infirmus : confer French infirme . See In- not, and Firm , adjective ]
1. Not firm or sound; weak; feeble; as, an infirm body; an infirm constitution.

A poor, infirm , weak, and despised old man.

Shak.

2. Weak of mind or will; irresolute; vacillating. "An infirm judgment." Burke.

Infirm of purpose!

Shak.

3. Not solid or stable; insecure; precarious.

He who fixes on false principles treads or infirm ground.

South.

Syn. -- Debilitated; sickly; feeble; decrepit; weak; enfeebled; irresolute; vacillating; imbecile.

Infirm transitive verb [ Latin infirmare : confer French infirmer .] To weaken; to enfeeble. [ Obsolete] Sir W. Raleigh.

Infirmarian (ĭn`fẽr*mā"rĭ* a n) noun A person dwelling in, or having charge of, an infirmary, esp. in a monastic institution.

Infirmary (ĭn*fẽrm"ȧ*rȳ) noun ; plural Infirmaries (- rĭz). [ Confer Middle English fermerie , Old French enfermerie , French infirmerie , Late Latin infirmaria . See Infirm .] A hospital, or place where the infirm or sick are lodged and nursed gratuitously, or where out-patients are treated.

Infirmative adjective [ Confer French infirmatif .] Weakening; annulling, or tending to make void. [ Obsolete]

Infirmatory noun An infirmary. [ Obsolete]

Infirmity noun ; plural Infirmities . [ Latin infirmitas : confer French infirmite . See Infirm , adjective ]
1. The state of being infirm; feebleness; an imperfection or weakness; esp., an unsound, unhealthy, or debilitated state; a disease; a malady; as, infirmity of body or mind.

'T is the infirmity of his age.

Shak.

2. A personal frailty or failing; foible; eccentricity; a weakness or defect.

Will you be cured of your infirmity ?

Shak.

A friend should bear his friend's infirmities .

Shak.

The house has also its infirmities .

Evelyn.

Syn. -- Debility; imbecility; weakness; feebleness; failing; foible; defect; disease; malady. See Debility .

Infirmly adverb In an infirm manner.

Infirmness noun Infirmity; feebleness. Boyle.

Infix transitive verb [ imperfect & past participle Infixed ; present participle & verbal noun Infixing .] [ Latin infixus , p. p of infigere to infix; prefix in- in + figere to fix: confer French infixer . See Fix .]
1. To set; to fasten or fix by piercing or thrusting in; as, to infix a sting, spear, or dart. Shak.

The fatal dart a ready passage found,
And deep within her heart infixed the wound.

Dryden.

2. To implant or fix; to instill; to inculcate, as principles, thoughts, or instructions; as, to infix good principles in the mind, or ideas in the memory.

Infix noun Something infixed. [ R.] Welsford.

Inflame transitive verb [ imperfect & past participle Inflamed ; present participle & verbal noun Inflaming .] [ Middle English enflamen , Old French enflamer , French enflammer , Latin inflammare , inflammatum ; prefix in- in + flammare to flame, from flamma flame. See Flame .]
1. To set on fire; to kindle; to cause to burn, flame, or glow.

We should have made retreat
By light of the inflamed fleet.

Chapman.

2. Fig.: To kindle or intensify, as passion or appetite; to excite to an excessive or unnatural action or heat; as, to inflame desire.

Though more, it seems,
Inflamed with lust than rage.

Milton.

But, O inflame and fire our hearts.

Dryden.

3. To provoke to anger or rage; to exasperate; to irritate; to incense; to enrage.

It will inflame you; it will make you mad.

Shak.

4. (Medicine) To put in a state of inflammation; to produce morbid heat, congestion, or swelling, of; as, to inflame the eyes by overwork.

5. To exaggerate; to enlarge upon. [ Obsolete]

A friend exaggerates a man's virtues, an enemy inflames his crimes.

Addison.

Syn. -- To provoke; fire; kindle; irritate; exasperate; incense; enrage; anger; excite; arouse.

Inflame intransitive verb To grow morbidly hot, congested, or painful; to become angry or incensed. Wiseman.