International law

The sixteenth entry is l’esecuzione in buona fede, and the phrase inside it is the one place on this list where English did not choose. Italian turned the Latin bona fide into words of its own and uses nothing else: l’acquirente in buona fede, trattare in buona fede, essere in buona fede. English did that too, and « in good faith » is what a treaty says. But it also carried the Latin over untouched, and the borrowed form then went to work on its own. Bona fide in English stands as an adjective before a noun — « a bona fide offer », « a bona fide purchaser » — where the Latin was an adverbial phrase, with good faith, which no adjective can be. From that adjective the language built a noun that looks like a plural and is none: « her bona fides ». It does not mean her honesty. It means the papers showing she is who she claims to be, so « we checked his bona fides » describes a file rather than a state of mind. One Latin phrase, two English forms, and only the translated one carries the duty the treaty imposes.