Malapropism

A malapropism (from French mal à propos, "badly to the point") is an incorrect usage of a word, usually with comic effect. The term comes from the character, Mrs Malaprop, in Richard Brinsley Sheridan's comedy, The Rivals[?] (1775). Here are some examples from her dialogue:

"He's as headstrong as an allegory on the banks of the Nile." (I.e. alligator)

"He is the very pineapple of politeness". (I.e. pinnacle)

"If I reprehend any thing in this world, it is the use of my oracular tongue, and a nice derangement of epitaphs!" (I.e., apprehend; vernacular; arrangement; epithets)

Common malapropisms in modern English include use of:

• Disinterested (impartial, unbiased) for uninterested ("A judge should be disinterested, but not uninterested")
• Fortuitous (random, by chance) for fortunate
• In the ascendancy for in the ascendant ("One has the ascendancy" vs "One is in the ascendant")
• Barbaric for barbarous ("Barbaric" can be positive and is used of culture, "barbarous" is negative and used of behavior: "Barbaric splendor" vs "Barbarous cruelty")

See also:

• Fowler's Modern English Usage
• Pleonasm
• Elegant variation