Keep a straight face

Meaning

Maintain a neutral expression despite strong emotion.

Usage

Used when composure is required.

Origin & History

Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.

Learned from etiquette instructions about poise.

Long used on stage and in social manuals.