'antifascist' originates from English formation combining the prefix 'anti-' (from Greek 'antí' meaning 'against') with 'fascist' (from Italian 'fascista', relating to 'fascismo').

'antifascist' developed in English in the 20th century as a compound (often seen hyphenated as 'anti-fascist') in response to the rise of 'fascism' (from Italian 'fascismo', from 'fascio' meaning 'bundle' or 'group'). The element 'fascist' entered English via Italian and French before settling into modern English usage.

Initially used specifically to describe opposition to the historical movements of 1920s–1940s fascism, it has since broadened to refer more widely to opposition to fascist or extreme authoritarian movements and ideology.