'antispir(o)chetal' is a modern formation from the prefix 'anti-' (Greek, meaning 'against'), the noun 'spirochete' (New Latin 'Spirochaeta', from Greek elements 'speira' meaning 'coil' and 'chaite' meaning 'hair'), and the adjectival suffix '-al'.

'spirochete' was coined in New Latin as 'Spirochaeta' (19th century) from Greek roots 'speira' and 'chaite'; medical formations such as 'antispirochetal' emerged in 20th-century biomedical English by combining 'anti-' + 'spirochete' + '-al'. The parenthetical form 'antispir(o)chetal' reflects an optional linking vowel 'o' seen in some variant spellings.

Initially the components simply denoted 'against' + 'spirochete'; over time the combined term came to be used specifically in medical contexts to describe substances or agents active against spirochetal bacteria.