poker face
一本正经的面容； 面无表情的人
原意是指打牌时持牌人面无表情，他人无法从他脸上的表情判断他手里持的牌是好还是坏。
poker face
noun
1.
an expressionless face: He can tell a funny story with a poker face.
2.
a person who has or deliberately assumes a poker face: It is impossible to tell what that poker face is really thinking.
--------------------------------------------------------------------------------
Origin:
1880–85, Americanism
World English Dictionary
poker face
— n
informal a face without expression, as that of a poker player attempting to conceal the value of his cards
Idioms & Phrases
poker face
A visage lacking any expression that can be interpreted, as in Whenever Betty attended one of her children's performances, she managed to keep a poker face . This term alludes to the facial expression of a poker player who is expert at concealing his feelings about his hand. [c. 1880]
URL: http://dictionary.reference.com/browse/poker+face
Early usage of the term, poker face, outside the game of poker, was seen in 1920s by American sportswriters, describe player appearing unaffected during stressful games.[3] It used is often by Mental health professionals with their patients and by marketeers and salespeople during business negotiations.[4]
The term poker face has been used often in media, for example, Lady Gaga's song, "Poker Face" (2008) and television game show, PokerFace (2006–2007).
http://en.wikipedia.org/wiki/Blank_expression
