A malapropism is a linguistic mistake where a person uses a word that sounds similar to the intended word but has a completely different meaning. This often results in humorous or nonsensical statements. The term comes from the character Mrs. Malaprop in Richard Brinsley Sheridan's play "The Rivals," who frequently misuses words. Malapropisms can occur in everyday conversation and writing, often leading to confusion or laughter. They highlight the importance of vocabulary and understanding word meanings. Famous examples include saying "He is the pineapple of politeness" instead of "He is the pinnacle of politeness."