Definition of keep one's countenance in US English:

keep one's countenance

phrase

  • Maintain one's composure, especially by refraining from laughter.

    • ‘For my part I decided that for once in my life it was wisest to keep my countenance.’
    • ‘Party leaders, however, apparently kept their countenance to avoid getting involved in any issues related to party reform.[, waiting to see what President Chen wanted, Hong said.]’
    • ‘Dislike welled up inside me, but I managed to keep my countenance and voice cordial.’
    • ‘Rachel could continue to sense his scrutiny, and because of that kept her countenance strictly controlled.’