In psychoanalysis, a Freudian slip, also called parapraxis, is an error in speech, memory, or physical action that occurs due to the interference of an unconscious subdued wish or internal train of thought. Classical examples involve slips of the tongue, but psychoanalytic theory also embraces misreadings, mishearings, mistypings, temporary forgettings, and the mislaying and losing of objects.
The Freudian slip is named after Sigmund Freud, who, in his 1901 book The Psychopathology of Everyday Life, described and analyzed a large number of seemingly trivial, even bizarre, or nonsensical errors and slips, most notably the Signorelli parapraxis.
Freud, himself, referred to these slips as Fehlleistungen (meaning "faulty functions", "faulty actions" or "misperformances" in German); the Greek term parapraxes (plural of parapraxis; ) was the creation of his English translator, as is the form "symptomatic action".
Freud's process of psychoanalysis is often described as being lengthy and complex, as was the case with many of the dreams in his 1899 book The Interpretation of Dreams. An obstacle that faces the non-German-speaking reader is such that in original German, The Interpretation of Dreams, Freud's emphasis on "slips of the tongue" leads to the inclusion of a great deal of colloquial and informal material that are extremely resistant to translations.
As in the study of dreams, Freud submits his discussion with the intention of demonstrating the existence of unconscious mental processes in the healthy:
In the same way that psycho-analysis makes use of dream interpretation, it also profits by the study of the numerous little slips and mistakes which people make—symptomatic actions, as they are called ... I have pointed out that these phenomena are not accidental, that they require more than physiological explanations, that they have a meaning and can be interpreted, and that one is justified in inferring from them the presence of restrained or repressed impulses and intentions.