'antonym' originates from Greek, specifically the word 'antonymon' (Greek 'antōnymon'), where 'anti-' meant 'against' and 'onoma' (or 'onym-') meant 'name'.

'antonym' changed from the Greek word 'antōnymon' and passed into scholarly Latin/Neo-Latin forms before becoming the modern English word 'antonym' in the 17th century.

Initially, it meant 'opposite name', but over time it evolved into its current meaning of 'a word with the opposite meaning to another word'.