Claim: The Freudian slip, also known as parapraxis, is a concept that is a part of classical psychoanalysis and is named after Sigmund Freud—who referred to these as Fehlleistungen (“faulty functions”).
Evidence: 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. The concept is part of classical psychoanalysis. 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; from Greek παρά (para) 'another', and πρᾶξις (praxis) 'action') was the creation of his English translator, as is the form "symptomatic action".