Region: General | Usage example: He accepted the bonus graciously, not looking a gift horse in the mouth.

Don't look a gift horse in the mouth

Meaning

Accept gifts gratefully without critiquing them.

Used when someone might focus on flaws instead of gratitude.

Origin notes can vary by region and source; this page gives the commonly reported explanation and usage context.

Evaluating a horse's age by checking its teeth.

Proverb recorded as early as the 4th century, popular in English since the 16th.