unflappable Synonyms

imperturbable as cool as a cucumber laid-back unagitated undisturbed unshakable unruffled unmoved tranquil together stolid stoical stoic easygoing level-headed levelheaded well-adjusted unperturbed unflustered unemotional unbothered self-controlled untroubled unfazed unexcitable even-tempered coolheaded steady sober serene easy dispassionate detached cool-headed cool controlled confident composed collected chilled centered calm equable equanimous self-possessed self-confident sedate relaxed quiet poised