In human interactions, good faith (bona fides) is a sincere intention to be fair, open, and honest, regardless of the outcome of the interaction. Some Latin phrases have lost their literal meaning over centuries, but that is not the case with bona fides, which 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). 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, and it 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. The modern interpretation is that it is a return of favor for the completion of a favor. In contemporary English, 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. Good faith (law) In law, bona fides denotes the mental and moral states of honesty and conviction regarding either the truth or the falsity of a proposition, or of a body of opinion; likewise regarding either the rectitude or the depravity of a line of conduct. As a legal concept, bona fides is especially important in matters of equity. The concept of bona fide is also proclaimed by the original version of Magna Carta. In contract law, the implied covenant of good faith is a general presumption that the parties to a contract will deal with each other honestly and fairly, so as not to destroy the right of the other party or parties to receive the benefits of the contract.