'anti-fascistic' originates from a modern English formation combining the prefix 'anti-' (from Greek 'anti', meaning 'against') and 'fascistic' (ultimately from Italian 'fascismo', from 'fascio').

'fascism' developed from Italian 'fascismo' in the early 20th century, itself from 'fascio' (a 'bundle' or 'league'), influenced by the Latin 'fasces'; 'fascistic' was formed from 'fascism' with the adjectival suffixes '-ic'/'-istic', and 'anti-' was prefixed in English to produce 'anti-fascistic' in contexts opposing fascist movements (notably from the 1920s–1940s onward).

Initially 'fascio' meant a physical 'bundle' or 'league'; over the 20th century 'fascism' came to denote a specific authoritarian political movement, and 'anti-fascistic' evolved to mean 'opposed to fascism' in political and social contexts.