the word 'unawares' is a compound formed from the negative prefix 'un-' and the adjective 'aware', with the addition of the adverbial '-s' suffix. 'aware' itself originates from old english 'gewær', meaning "watchful, cautious," a state of being informed or conscious. the '-s' suffix, common in forming adverbs from adjectives in middle english, solidified its grammatical role. thus, the literal construction "not in a state of being watchful or conscious" evolved to describe the modern abstract sense of acting or happening without prior knowledge or expectation.

Structure: un (not) + aware (conscious) + s (adverbial suffix) - un: a prefix of old english origin, meaning "not," used to form negatives. - aware: an adjective of old english origin, from the elements 'ge-' (intensive) + 'wær' (cautious, wary). - s: an adverbial suffix of middle english origin, added to adjectives to form adverbs (e.g., besides, towards).