'anti-medievalist' originates from the Greek prefix 'anti-' meaning 'against' combined with 'medievalist.' The element 'medieval' comes from Medieval Latin 'medius aevum' meaning 'middle age,' and the agentive suffix '-ist' (via Latin/Old French from Greek '-istēs'/'-ista') meaning 'one who advocates or studies.'

'medieval' developed from Medieval Latin 'medius aevum' ('middle age') into Old French and Middle English as 'medieval,' then the noun/agent form 'medievalist' was formed in modern English to denote a scholar or advocate of medieval studies or medievalism. 'Anti-' was prefixed to create 'anti-medievalist' to indicate opposition.

Initially the components referred separately to 'against' + 'middle ages'/'advocate of the middle ages.' Over time the compound came to mean specifically 'a person (or stance) opposing medievalism or the romantic/study-oriented revival of medieval ideas,' rather than a literal opposition to the historical period itself.