'bacchanalianly' originates from English, formed from the adjective 'bacchanalian' + the adverbial suffix '-ly', where 'bacchanalian' comes from 'Bacchanalia' (Latin) referring to festivals of Bacchus.

'bacchanalianly' developed from the English adjective 'bacchanalian' (17th century), which in turn came from Latin 'Bacchanalia' (name of the Roman festivals), and that Latin term was borrowed from Greek 'Bakkhanalia' related to 'Bakkhos' (the god Bacchus/Dionysus).

Initially connected specifically to the Roman festivals of Bacchus (religious rites and celebrations), it evolved to mean general excessive, drunken revelry and then formed the adverb 'bacchanalianly' to describe actions done in that manner.