Main Entry: im·per·turb·able

Pronunciation: \ˌim-pər-ˈtər-bə-bəl\

Function: adjective

Etymology: Middle English, from Late Latin imperturbabilis, from Latin in- + perturbare to perturb

Date: 15th century

: marked by extreme calm, impassivity, and steadiness : serene

synonyms see cool

— im·per·turb·abil·i·ty \-ˌtər-bə-ˈbi-lə-tē\ noun

— im·per·turb·ably \-ˈtər-bə-blē\ adverb