Good faith (Latin: bona fides), in human interactions, is a sincere intention to be fair, open, and honest, regardless of the outcome of the interaction. While some Latin phrases lose their literal meaning over centuries, this is not the case with bona fides; it is still widely used and interchangeable with its generally accepted modern-day English translation of good faith. It is an important concept within law and business. The opposed concepts are bad faith, mala fides (duplicity) and perfidy (pretense). In contemporary English, the usage of bona fides is synonymous with credentials and identity. The phrase is sometimes used in job advertisements, and should not be confused with the bona fide occupational qualifications or the employer's good faith effort, as described below.
Bona fides is a Latin phrase meaning "good faith". Its ablative case is bona fide, meaning "in good faith", which is often used as an adjective to mean "genuine". While today fides is concomitant to faith, a more technical translation of the Latin concept would be something like "reliability", in the sense of a trust between two parties for the potentiality of a relationship. In ancient Rome bona fides was always assumed by both sides, had implied responsibilities, and both legal and religious consequences if broken. Fides was one of the original virtues to be considered a religious "divinity" in Roman paganism. Modern interpretation is that it is a return of favor for the completion of a favor.