adjective

having one’s feelings and expression under control; calm.

a very talented and composed young player

calm,collected,cool,and collected,as cool as a cucumber,cool-headed,controlled,self-controlled,serene,tranquil,relaxed,at ease,self-possessed,unruffled,unperturbed,unflustered,undisturbed,unmoved,unbothered,untroubled,unagitated,equable,even-tempered,level-headed,imperturbable,unflappable,unfazed,together,laid-back,chilled,nonplussed,equanimous