'bankruptly' is formed in English from the adjective 'bankrupt' + the adverbial suffix '-ly'. 'bankrupt' itself originates from Italian (via Old French) from the word 'bancarotta'/'banqueroute', where 'banca'/'banque' meant 'bench' (a moneylender's table) and 'rotta'/'route' meant 'broken'.

'bankrupt' entered Middle English from Old French 'banqueroute' (literally 'bench broken' referring to a broken money‑changer's table); this developed into the modern English 'bankrupt', and the adverb 'bankruptly' was later formed by adding '-ly'.

Initially it referred literally to a 'broken bench' (the breaking of a moneylender's table as a sign of failure to pay), meaning inability to meet debts; over time it evolved to mean 'insolvent' or 'financially ruined', and the adverbial form came to mean 'in a bankrupt (or utterly lacking) manner'.