screw loose

In real, traceable use. Part of the curated seed collection; community review is coming.

Sense 1

Meaning · English

A state of insanity or eccentricity.

Register: slang

Where it’s used: Used American English

Examples

I think there's a screw loose in that brain of hers!

Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30)

Sources & notes

Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).

Sense 2

Meaning · English

A state of enmity or disagreement.

Register: archaic, slang

Sources & notes

Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).

Sense 3

Meaning · English

When friends become cold and distant towards each other, it is said there is a SCREW LOOSE betwixt them; the same phrase is also used when anything goes wrong with a person’s credit or reputation.

Era: ca. 1874 (Victorian)

Where it’s used: Origin British & Irish English
Sources & notes

Historical definition reproduced from Hotten’s The Slang Dictionary (1874, public domain; Project Gutenberg #42108, retrieved 2026-07-31). Reflects the attitudes of its era.

Common questions

What does “screw loose” mean?

A state of insanity or eccentricity.

Is “screw loose” formal or informal?

screw loose is generally slang.