'antimedievalist' originates from Greek and Latin elements via English: specifically the prefix 'anti-' from Greek 'anti' meaning 'against', combined with 'medieval' from Latin 'medium aevum' meaning 'middle age', plus the agentive suffix '-ist' (via French/Latin) meaning 'one who'.

'antimedievalist' formed in modern English by combining the existing adjective/noun 'medieval' with the prefix 'anti-' and the suffix '-ist' to denote an agent; it is a contemporary compound rather than a word with a long historical lineage.

Initially it would simply denote 'one against medievalism'; over time its use can broaden to refer to critics of medievalist scholarship, revival movements, or medieval-inspired ideologies.