'anti-American' originates from the Greek prefix 'anti-' (from Greek 'anti', meaning 'against') combined with 'American' (from 'America', the name for the continents/nation associated with Amerigo Vespucci).

'anti-' was borrowed into English from Greek via Latin and Old French, and 'American' derives from the proper name 'America' (from the Latinized form of 'Amerigo'). The compound 'anti-American' formed in modern English usage in the 19th–20th centuries to describe opposition to America or American policy.

Initially it literally meant 'against America' (i.e., opposed to America or Americans); over time it has retained that core sense but has also been used rhetorically or politically to label critics, sometimes with broader cultural or ideological implications.