'anti-Anselm' originates as a compositional formation in modern English: the prefix 'anti-' originates from Greek, specifically the word 'anti' where the prefix meant 'against', combined with the proper name 'Anselm' (from the medieval Latin 'Anselmus').

'anti-' entered English via Latin and French as a combining prefix meaning 'against'; 'Anselm' changed from Old Germanic 'Anshelm' (elements 'ans' + 'helm') through medieval Latin 'Anselmus' into the modern English proper name 'Anselm'. The compound 'anti-Anselm' is a modern English hyphenated formation using the Greek-derived prefix plus the proper name.

Initially, the prefix-plus-name formation simply meant 'against Anselm (the man)'; over time it has come to be used more specifically of opposition to 'Anselm's views' (for example, his ontological argument), a nuance that is common in contemporary philosophical usage.