bona fide
The Latin phrase meaning genuine.
Write bona fide as two words: a bona fide offer. It is an adjective, and sometimes an adverb: bona fide surprised. The noun is bona fides: check his bona fides. Do not write bonafide or bona-fide in ordinary prose.
Examples
Use It was a bona fide offer.
Use Check her bona fides.
Avoid a bonafide offer