'antiheroism' originates from English compounds: 'anti-' (prefix) + 'hero' + the suffix '-ism'. 'anti-' comes from Greek 'anti-' meaning 'against' or 'opposite', 'hero' comes from Greek 'hērōs' meaning 'hero', and '-ism' (via Latin/Greek) denotes 'state, quality, or practice'.

'antiheroism' formed by combining the noun 'antihero' (a term that arose in modern literary criticism in the 19th–20th century to label protagonists who contrast with classical heroes) with the abstract noun-forming suffix '-ism', producing a word that denotes the state or quality related to antiheroes.

Initially used to describe the presence or characteristics of an 'antihero' (a protagonist lacking heroic attributes), it has come to cover both the traits of such characters and the broader cultural or literary tendency to feature or valorize them.