'antimaniacal' originates from the combining prefix 'anti-' (from Greek 'anti' meaning 'against') and 'maniacal' (derived from 'maniac', from Greek 'mania' meaning 'madness').

'mania' comes from Greek 'mania' (madness), which gave rise to 'maniakos'/'maniac' in Late Greek and Latin; English 'maniacal' developed by adding the adjectival suffix '-al' to 'maniac'; 'antimaniacal' is a modern English formation by prefixing 'anti-' to 'maniacal'.

Initially the elements meant 'against' + 'madness'; the combined form has retained the sense of opposition to mania, and has also been extended figuratively to mean opposition to extreme enthusiasm or fanaticism.