"poser" in the noun sense
1. poseur, poser
a person who habitually pretends to be something he is not
2. model, poser
a person who poses for a photographer or painter or sculptor
"the president didn't have time to be a model so the artist worked from photos"
3. poser, stumper, toughie, sticker
a particularly difficult or baffling question or problem
Source: WordNet® (An amazing lexical database of English)
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