Wearing a particularly stern and disapproving expression; humorless; priggish.(adjective)
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Use "po-faced" in a sentence
"Formula One is a notoriously po-faced sport but Sebastian Vettel – a fan of Monty Python and Little Britain – was not too distracted by the task of trying to win Sunday's Chinese grand prix to be amused by the sight of an absent-minded Jenson Button driving his McLaren into the Red Bull pit, just as Vettel himself was attempting to make a tyre stop."
"There has been something of a po-faced flap at some US media outlets about this weekend's rallies in Washington arranged by TV news satirists Jon Stewart and Stephen Colbert."
"Pontevedro, in Giles Havergal's enticingly louche production, is one of those po-faced principalities whose chief characteristic is taking itself just a little too seriously."