A malapropism (also called a malaprop, acyrologia, or Dogberryism) is the mistaken use of an incorrect word in place of a word with a similar sound, resulting in a nonsensical, sometimes humorous utterance. An example is the statement attributed to baseball player Yogi Berra, regarding switchhitters, "He hits from both sides of the plate. He's amphibious." Malapropisms often occur as errors in natural speech and are sometimes the subject of media attention, especially when made by politicians or other prominent individuals. Philosopher Donald Davidson has said that malapropisms show the complex process through which the brain translates thoughts into language.

Humorous malapropisms are the type that attract the most attention and commentary, but bland malapropisms are common in speech and writing.