'anti-cynic' is a modern compound formed from the prefix 'anti-' and the noun 'cynic'. 'anti-' ultimately comes from Greek 'anti-' meaning 'against', and 'cynic' comes from Greek 'kynikos' meaning 'dog-like' (used for members of the Cynic philosophical school).

'cynic' came into English via Latin/Old French from Greek 'kynikos' (κυνικός). The prefix 'anti-' has been used in English since Late Latin/Old French borrowings and has been productively attached to nouns and adjectives in modern English to form compounds such as 'anti-cynic'. The compound 'anti-cynic' is a relatively recent English formation using these established elements.

Originally, 'cynic' referred to a follower of the Cynic school (literally 'dog-like'); over time it came to mean someone distrustful of human motives. 'Anti-cynic' therefore developed to mean 'against cynicism' or 'not cynical; showing trust/optimism' rather than having an independent, older historical sense.