(of a person) not favouring a particular side, opinion etc (in a quarrel)

unfeeling, impartial

(of a person) showing no sign of feeling

aloof, cool

not easy troubled or excited

calm, collected

having or showing no interest or enthusiasm

easy-going, laid back

too confident

confident

having, showing patience; a person who has received or is receiving medical treatment

capable, willing to endure

preferring or enjoying, peace; calm; quiet

friendly, serene

(of a person, behaviour) guided by reason and not feelings

reflective

calm; not easily annoyed

calm, mild

(of a person, character) slow to express feelings or opinions; (of a seat in a train, room in a hotel etc) kept for a person's later use

silent, unsociable; constrained

(of a person, behaviour) calm; serious; to give (a person) sedative

calm, collected

happy and calm

calm, undisturbed

(of a person, appearance, behaviour etc) conservative, quiet and serious

restrained, set

showing, behaving with, self-control; (of parts of the world) free from extremes of heat and cold

calm, moderate

calm; quiet

quiet, peaceful

(of a person, behaviour) not becoming excited or nervous during a crisis

cool and calm

calm; not upset or agitated

calm