Definition of “have a screw loose” - English Dictionary

american-english dictionary

“have a screw loose” in British English

See all translations

have a screw loose

informal

If you say that someone has a screw loose, you mean that they behave in a strange way and seem slightly mentally ill.

(Definition of “have a screw loose” from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)

“have a screw loose” in American English

See all translations

have a screw loose

infml to seem crazy:

Her brother definitely has a screw loose – I don't really trust him.

(Definition of “have a screw loose” from the Cambridge Academic Content Dictionary © Cambridge University Press)