The phrase bona fide comes directly from the Latin bona fides, which means, roughly, good faith. In modern English, bona fide (without the s) is usually an adjective meaning (1) made or carried out in good faith or (2) real or genuine. Bona fides, with the s at the end, is a noun meaning (1) good faith, (2) credentials, or (3) information that establishes a person’s reputation or credentials.
There are several usage issues involving these terms. First, the Latin bona fides is actually singular, yet writers almost always treat it as plural. Bona fide, meanwhile, was originally a legal term meaning without fraud, and it was an adverb. It developed its modern meaning through centuries of poor usage. Because of these and other issues, bona fide and bona fides might be best avoided. There are perfectly good alternatives. For example, genuine or honest can replace bona fide, and good faith or credentials can often replace bona fides.
If you do use either of these terms, don’t forget to make it two words (and bonified is not a dictionary-recognized word). There’s no need to italicize these long-established loanwords.
Examples
In the following examples, the writers demonstrate the conventional modern use of bona fide:
While Kim is a bona fide mogul worth a reported $35 million, her fiancé isn’t bad off either. [Los Angeles Times]
By now, they are bona fide celebrities, with their own branded trainers, energy drinks and bobble-head dolls … [Guardian]
The German board game has become a bona fide social phenomenon. [Globe and Mail]
And the following examples show how bona fides is usually used:
The Liberal party must earn its modern economic bona fides and not rest on past laurels. [National Post]
It’s a sign of the times that the more conservative Romney 2.0 is having to defend his ideological bona fides. [New Republic]
Those back-slapping bona fides are helpful now that the feds are weighing a host of new rules that has bankers itchy. [Wall Street Journal]
Notice how the last writer treats bona fides as plural, even though the term is technically singular. We don’t claim this is correct or incorrect. It’s just the way the word is used.
