From Longman Dictionary of Contemporary Englishstiff upper lipstiff upper lipCALMthe ability to stay calm and not show your feelings in a difficult or upsetting situation Men were taught to keep a stiff upper lip. → stiff
Examples from the Corpus
stiff upper lip• Election losers, for instance, are traditionally expected to keep a stiff upper lip and not let their disappointment show.• The Ulster Unionist security spokesman maintained a stiff upper lip as he had his moustache shaved off - for charity.• Paul didn't keep a stiff upper lip because that was the way that he thought that Christians should behave.• The stiff upper lip is a barrier against the trembling which could lead to tears.• So please, leave the stiff upper lip to one side, at home at least.• All he could produce was a stiff upper lip, while young Lady C cast meaningful looks at sturdy gamekeeper Mellors. 