Claim: The Freudian slip is named after Sigmund Freud in which he described and analyzed a lot of trivial, bizarre or nonsensical errors and slips and referred to these as Fehlleistungen (“faulty functions").
Evidence: 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".