Malapropism
The mistaken use of a word in place of a similar-sounding one, often to comic effect.
A malapropism swaps in the wrong word—one that sounds like the intended one but means something absurdly different. Writers use it to make a character comic, pretentious, or endearingly muddled. The humor comes from the gap between what is said and what was meant.
Example
The constable Dogberry mangles his words—declaring suspects should be “comprehended” rather than apprehended—making his self-importance ridiculous.
Much Ado About Nothing · William Shakespeare
See it in action
Analyses on StoryBites that use malapropism: