tell

A tell in poker is a change in a player's behavior or demeanor that is claimed by some to give clues to that player's assessment of their hand. A player gains an advantage if they observe and understand the meaning of another player's tell, particularly if the tell is unconscious and reliable. Sometimes a player may fake a tell, hoping to induce their opponents to make poor judgments in response to the false tell. More often, people try to avoid giving out a tell, by maintaining a poker face regardless of how strong or weak their hand is.