poker face

Sort of. It is more in the negative side. It can be explained as follows:
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.

2009-01-30 01:58:35 補充：
I just talked to a White, and she said poker face is neither negative nor positive.

Poker-face - 正是指一個人喜怒不形於色.
Well, most of the time it's possetive (正面), sometimes is even a compliment.
例: John has a poker face, so no one can tell whether he's a winner or loser of the game.
笑面虎 - 是指某人性格陰險, 笑裡藏刀.
例: Jack is a pretty tricky fellow, he shows no sign to do anything evil.
tricky (adj) = 狡猾的
shows no sign = 不形予色 = 陰濕.


2009-01-30 14:52:47 補充：
Sorry, mis-spelt the word of 2nd line: possetive - should be positive