'antiheroic' originates from Modern English, specifically formed from 'antihero' + the adjectival suffix '-ic', where 'anti-' meant 'against' and '-ic' formed adjectives meaning 'related to' or 'characteristic of'.

'antiheroic' developed from the noun 'antihero' (formed from Greek-derived prefix 'anti-' + 'hero' from Greek 'hērōs') with the addition of the suffix '-ic' (via Latin/French adjectival formation), producing the adjective 'antiheroic' in Modern English.

Initially it meant 'of or pertaining to an antihero' (i.e., relating to a character who opposes conventional heroic qualities); over time it has come to describe the specific quality of lacking traditional heroism—morally ambiguous, flawed, or unconventional—in characters or actions.