screw loose

noun2

1. •
   (slang) A state of insanity or eccentricity.

   • I think there's a screw loose in that brain of hers!
2. •
   (slang, no longer used) A state of enmity or disagreement.

   • I understand there's a screw loose between you two, so I've brought Morton that you may shake hands, and be comfortable together. — 1830