Definition of poker face
What we mean by "poker face" is a neutral face, no matter what the situation, a face of ice, a face of impassive. Some beginning players will betray themselves with their facial expressions. For example, some players will be disinterested in the game until they have a hand to play. As soon as they receive their pair of aces or kings, their face lights up and they try unsuccessfully to hide their smile. This is the exact opposite of a poker face. The poker face will be the same when bluffing, when you have a Royal Flush, as it is when you have an average hand. No matter what hand we have, we should always have the same facial expression.
It's not just the poker face that betrays the poker face.
You've probably heard a lot about the "poker face" as an element that can betray a poker player, but there are many other clues to an opponent's hand. First, many players will have their pupils dilated when they have a very strong hand. Others may have sweaty or shaky hands when they have a big game. Some players may even have drops of sweat on their foreheads when they have a very strong hand. If you're playing live poker, keep an eye out for these little things!