adj

loony

LOO-nee

Loony (adj) means Crazy or mentally unstable. Example: “That's a completely loony idea.”

adj

Crazy or mentally unstable.

"That's a completely loony idea."

"He went a bit loony after weeks without sleep."

Extremely silly or ridiculous.

"The plot of the movie was loony but fun."

noun

An informal word for a foolish or unstable person.

"Only a loony would try to cross that river in a storm."

How to use loony

Learner’s notes

In plain EnglishCrazy, silly, or someone acting that way — used casually, often affectionately.

When to use it

Informal; can sound insensitive when applied to real mental illness, so it's mostly used for silly behaviour or ideas rather than clinical conditions.

Easily confused with

loon → looney →

Word forms

loonier comparative, loonies plural, looniest superlative

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That's a completely _____ idea.

Etymology

A shortened, informal version of "lunatic."

Synonyms

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crazy weirdo looney nutcase

Related words

crazy fantastic insane nuts bugs creep bats rum

Rhymes for loony

Sony Tony pony bony ebony agony phony irony peony Stony Saxony colony

See all rhymes for loony →

Frequently asked questions

What does “loony” mean?

The word “loony” means crazy or mentally unstable. In plain terms, crazy, silly, or someone acting that way — used casually, often affectionately.

How do you pronounce “loony”?

“Loony” is pronounced LOO-nee (/ˈluːni/ in IPA).

How do you use “loony” in a sentence?

Here is “loony” used in a sentence: “That's a completely loony idea.”

What part of speech is “loony”?

Depending on how it is used, “loony” can be an adjective and a noun.

How many meanings does “loony” have?

“Loony” has 3 distinct senses listed in this dictionary. The most common is: crazy or mentally unstable.

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