1) Aplomb 2) Assurance 3) Assuredness 4) Calmness 5) Cool 6) Equanimity 7) Poise 8) Serenity 9) Temper 10) Tranquility 1) Calm 2) Calmness 3) Coolness 4) Disposition 5) Equability 6) Equanimity 7) Level-headedness 8) Peace of mind 9) Poise 10) Puce rooms generate calmness 11) Self-control 12) Self-possession 13) Serenity 14) Temperament 
• (n.) A combination; a union; a bond. • (n.) Orderly adjustment; disposition. • (n.) A settled state; calmness; sedateness; tranquillity; repose. • (n.) Frame; make; temperament. • (n.) The act of composing, or that which is composed; a composition.
Com·po'sure noun [ From Compose .] 1. The act of composing, or that which is composed; a composition. [ Obsolete] « Signor Pietro, who had an admirable way both of composure [ in music] and teaching. Evelyn. » 2. Orderly adjustment; disposition. [ Ob...
[n] - steadiness of mind under stress
composure 1. A calm or tranquil state of mind; self-possession or self control. 2. Steadiness of mind under stress: 'The father accepted his daughter's problems with composure and the mother reacted with equanimity.' 3. Calm and steady control over the emotions.
calm noun steadiness of mind under stress; `he accepted their problems with composure and she with equanimity`
serene, self-controlled state of mind; calmness; tranquillity: Despite the hysteria and panic around him, he retained his composure.
[SAT terms] steadiness of mind under stress[Literary terms] steadiness of mind under stress