keep a stiff upper lip
US /kiːp ə stɪf ˈʌpər lɪp/
UK /kiːp ə stɪf ˈʌpər lɪp/

1.
garder son sang-froid, ne pas montrer ses émotions, faire bonne figure
to remain brave and unemotional in a difficult or upsetting situation
:
•
Despite the bad news, she managed to keep a stiff upper lip.
Malgré la mauvaise nouvelle, elle a réussi à garder son sang-froid.
•
The soldiers were told to keep a stiff upper lip during the difficult mission.
On a dit aux soldats de garder leur sang-froid pendant la mission difficile.