the word 'unruffled' is a straightforward english formation built upon the verb 'ruffle'. 'ruffle' itself entered middle english from low germanic languages, carrying the sense of disturbing a smooth surface or disordering an arrangement. the prefix 'un-', of old english origin, is a common negator, while the '-ed' suffix transforms the past participle into an adjective describing a state. thus, the literal meaning "not having been disturbed" evolved to describe both a person's calm demeanor and a surface's undisturbed smoothness, perfectly capturing the absence of agitation.

Structure: un (not) + ruffle (to disorder) + ed (adjective suffix) un- (old english, a prefix meaning "not"); ruffle (middle english, from a low germanic base meaning "to disorder, wrinkle"); -ed (old english, a suffix forming adjectives with the sense "having the quality of").