keep a stiff upper lip
US /kiːp ə stɪf ˈʌpər lɪp/
UK /kiːp ə stɪf ˈʌpər lɪp/
1.
to remain brave and unemotional in a difficult or upsetting situation
:
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Despite the bad news, she managed to keep a stiff upper lip.
•
The soldiers were told to keep a stiff upper lip during the difficult mission.