'antimodernly' originates from the Greek prefix 'anti-' (ἀντί) meaning 'against', combined with 'modern' (from Latin/French 'modernus'/'moderne') where Latin 'modo' meant 'just now', plus the English adverbial suffix '-ly' (from Old English '-lic').

'antimodernly' developed by affixing the Greek-derived prefix 'anti-' to the adjective 'modern' (itself from French 'moderne' ← Latin 'modernus' ← Latin 'modo'), and then adding the adverbial suffix '-ly' (from Old English '-lic'), yielding the modern English adverb 'antimodernly'.

Originally the elements meant 'against' (anti-) and 'just now/recent' (modo), but over time 'modern' came to mean 'relating to present or recent times' and 'antimodernly' now means 'in opposition to modernity or modern styles'.