malapropism
definition
the mistaken use of a word in place of a similar sounding one, often with unintentionally amusing effect
example
Her continual malapropism during the speech led to laughter from the audience every time she misused a word.
synonyms
misuseblundergaffe
word origin — Coined in the 18th century from the character Madame Malaprop in Richard Brinsley Sheridan's play 'The Rivals' (1775), who was noted for her ludicrous misuse of words.