'poker-faced' originates from the game of 'poker', where players often maintain a neutral expression to conceal their emotions or intentions.

'poker' as a game term was adopted into English in the 19th century, and 'poker-faced' emerged as an adjective to describe someone with a neutral expression.

Initially, it referred to a neutral expression in poker games, but now it is used more broadly to describe anyone with an expressionless face.