imperturbable

Adjective

  1. not easily perturbed or excited or upset; marked by extreme calm and composure; “hitherto imperturbable, he now showed signs of alarm”; “an imperturbable self-possession”; “unflappable in a crisis”
  1. unable to be upset or excited; calm an imperturbable tranquillity

Origin

late Middle English : from late Latin imperturbabilis , from in- not + perturbare (see perturb )

Thesaurus

Adjective

  1. my father was a solid, imperturbable man

Similar Words: self-possessed composed collected calm cool, calm, and collected as cool as a cucumber cool-headed self-controlled poised tranquil serene relaxed easy-going unexcitable even-tempered placid sedate phlegmatic unperturbed unflustered untroubled unbothered unruffled undismayed unagitated undisturbed unmoved nonchalant at ease unflappable unfazed together laid-back nonplussed equanimous

Opposites: edgy excitable