poker face

English Thesaurus

1. a face without any interpretable expression (as that of a good poker player) (noun.attribute)

hypernym	:	countenance, visage,
definition	:	the appearance conveyed by a person's face (noun.attribute)

domain category	:	poker, poker game,
definition	:	any of various card games in which players bet that they hold the highest-ranking hand (noun.act)