# bona fide

idiom · CEFR C1

Source: https://englishreference.com/idiom/bona-fide
Updated: 2026-08-03

## Meaning

Genuine and honestly meant — the real thing, not a pretence.

## Examples

- It was a bona fide offer, not a joke.
- The discount is open to any bona fide student with a current enrolment card.
- Establishing that the buyer was bona fide decided the case, because a purchaser who paid a fair price with no notice of the earlier claim takes good title however badly the seller behaved.

## Origin

Bona fides — good faith — was not a decoration in Roman law but a working standard. A whole class of contracts, including sale, hire, partnership and agency, were bonae fidei: the judge was instructed to decide not by the strict letter of what was written but by what good faith required between the parties. It was the mechanism by which Roman law kept up with commercial reality. Bona fide is the ablative form, meaning in good faith, and English borrowed it as an adjective. A bona fide purchaser is one who bought honestly and without notice of anyone else's claim — still a live category in property law today. Ordinary English has loosened it to mean simply genuine: a bona fide offer, a bona fide expert. The plural noun bona fides went its own way and now means credentials — the evidence that someone is what they claim.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.