'antick' (modern 'antic') originates from Middle English 'antike' (or variant 'antick'), ultimately influenced by Old French 'antique' and Latin 'anticus', where the Latin root related to notions of 'ancient' or 'old'.

'antick' changed from Middle English 'antike' (also spelled 'antick'), influenced by Old French 'antique' and Latin 'anticus', and later took the modern English form 'antic' (with 'antick' attested as an older spelling).

Initially connected with 'ancient' or 'antique' via its Latin/French roots, the sense shifted in English to denote something grotesque, whimsical, or ludicrous — hence 'antic' meaning a clownish or extravagant gesture.