malapropism Definition

malapropism
noun

1. The unintentional misuse of a word, usually with comic effect, through confusion with another word that sounds similar but has a different meaning.
2. A word misused in this way. Compare Freudian slip.

Etymology: 18c: named after Mrs Malaprop, a character in Sheridan's play The Rivals (1775), who misuses words in this way; her name refers to the term malapropos.