The meaning of LOONY is foolish, eccentric. How to use loony in a sentence.

LOONY definition: 1. silly or stupid: 2. a person who is crazy, silly, or strange: 3. silly or stupid: . Learn more.

If you refer to someone as a loony, you mean that they behave in a way that seems mad, strange, or eccentric.

Jan 20, 2026 · Noun loony (plural loonies) (informal, offensive, derogatory) An insane or very foolish person.

loony (ˈluːnɪ) , looney or luny adj, loonier, looniest, lunier or luniest 1. lunatic; insane 2. foolish or ridiculous

Loony is an adjective that describes something or someone as being outside of their right mind, crazy, or lacking the ability to make logical decisions. Something can be loonier or looniest as well.

Definition of loony adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Loony definition: Extremely foolish or silly.

loony, n. & adj. meanings, etymology, pronunciation and more in the Oxford English Dictionary

“Now he’s a loony anti-vaxxer conspiracy theorist and running a campaign like a loon. It’s so embarrassing.”