malapropism
The blundering use of an absurdly inappropriate word or expression in place of a similar-sounding one.
uncountable
The script employed malapropism to great effect.
An instance of such use.
countable
The translator matched every malapropism in the original with one from his own language.
Where it comes from
From the name of Mrs. Malaprop, a character in the play The Rivals (1775) by Richard Brinsley Sheridan + -ism. As dramatic characters in English comic plays of this time often had allusive names, it is likely that Sheridan fashioned the name from malapropos (“inappropriate; inappropriately”), from French mal à propos. Mrs. Malaprop is a classic example of a familiar comedic character archetype who unintentionally substitutes inappropriate but like-sounding words that take on a ludicrous meaning when used incorrectly.
Related words
Adapted from the Wiktionary entry malapropism (CC BY-SA 4.0).