endeavour: [14] Despite its plausible appearance, endeavour is not a borrowing from French or Latin but a purely English creation. It was coined from the Middle English phrase put in dever, which was a partial translation of Old French mettre en deveir, literally ‘put in duty’, hence ‘make it one’s duty to do something’ (deveir, ancestor of modern French devoir ‘duty’, came ultimately from Latin dēbēre ‘owe’, source of English debit and debt). In the 14th century the last two words were joined together to form the verb endeavour ‘make an effort’. => debit, debt
