'epithetical' originates from Greek, specifically the word 'epitheton', where 'epi-' meant 'on, upon, attached to' and the root from 'tithenai' meant 'to place'. The English adjective is formed by adding the suffix '-ical' to 'epithet'.

'epithetical' developed from the noun 'epithet' (via Latin and Old French forms from Greek 'epitheton') and eventually entered English as the adjective 'epithetical' by combining 'epithet' with the adjectival suffix '-ical'.

Initially related to the idea of something 'placed on' a name or term (an added descriptor), it evolved into meanings referring to descriptive or qualifying words (epithets) and to speech characterized by such descriptors (often with an abusive or pejorative sense).