have a screw loose
phrase
variants
also have a loose screw
informal
: to be mentally unsound
He'll drive you crazy if you're not careful. He's got a screw loose and you know it.—
Jayne Anne Phillips
Jayne Anne PhillipsCite this Entry
“Have a screw loose.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/have%20a%20screw%20loose. Accessed 12 Dec. 2025.
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