Any inadvertent verbal or written mistake that reveals, or can be construed as revealing, an unconscious or repressed intention, belief, thought, attitude, etc. Named for the Sigmund Freud, considered the founding father of psychoanalysis, whose work largely focused on the unconscious and repressed elements of the human psyche. He said the wrong woman's name during his wedding ceremony, a Freudian slip that sent the bride-to-be into tears.