"Sucka" is a slang term used to describe someone who is considered inferior or lacks skill, often in a playful or derogatory manner. It conveys a sense of dismissal or superiority from the speaker toward the subject.
He missed the shot, and everyone called him a sucka.
She’s a sucka in the game, but no one tells her face-to-face.
Don’t act like you know everything—remember, you were a sucka once too.