1) Actionable 2) Dishonorable 3) Dishonourable 4) Illegal 5) Incompatible 6) Inequitable 7) Iniquitous 8) Undeserved 9) Unfair 10) Unrighteous 11) Unsporting 12) Unsportsmanlike 13) Wicked 1) An unjust ruler 2) Below the belt 3) Cheating 4) Dirty 5) Excessive 6) Foul 7) Inequitable 8) Iniquitous 9) Lacking fairness 10) Not exactly unfair 11) Not fair 12) Not just 13) Partial 14) Undeserved 15) Undue 16) Unfair 17) Unfaithful or dishonest 18) Unmerited 19) Unreasonable 20) Unsporting 21) Unsportsmanlike 
Source: Catton`s English Peerage, 1790 ...
• (a.) Acting contrary to the standard of right; not animated or controlled by justice; false; dishonest; as, an unjust man or judge. • (a.) Contrary to justice and right; prompted by a spirit of injustice; wrongful; as, an unjust sentence; an unjust demand; an unjust accusation.
That which is done against the perfect rights of another; that which is against the established law; that which is opposed to a law which is the test of right and wrong.
[adj] - not righteous 2. [adj] - violating principles of justice
unjust 1. Violating principles of justice or fairness; unfair. 2. Characterized by injustice; deficient in justice and fairness.
adjective violating principles of justice; `unjust punishment`; `an unjust judge`; `an unjust accusation`
not just; lacking in justice or fairness: unjust criticism; an unjust ruler. · unfaithful or dishonest.
[SAT terms] not fair; marked by injustice or partiality or deception