'anticlimactic' originates from the noun 'anticlimax' (formed from the prefix 'anti-' + 'climax'), where 'anti-' meant 'against' and 'climax' comes from Greek 'klimax' meaning 'ladder' or 'climax'.

'anticlimax' passed into English via Late Latin/French forms and was extended with the adjective-forming suffix '-ic' to become 'anticlimactic' in English; the adverb 'anticlimactically' was formed by adding '-ally'.

Initially it referred to a rhetorical drop or descent (a 'counter-climax' in sequence), but over time it evolved to describe any outcome or event that is disappointingly less exciting than expected.