have a screw loose

have a screw loose

1. (slang) To be insane, irrational, or eccentric.
   • 1873, Anthony Trollope, chapter 69, in The Eustace Diamonds:

     Richard, glorious in new livery, […] went with his sad message, first to the church and then to the banqueting-hall in Albemarle Street. "Not any wedding?" said the head-waiter at the hotel. "I knew they was folks as would have a screw loose somewheres."

   • 1916, Eleanor H. Porter, chapter 22, in Just David:

     "You know he really has got a screw loose in his head somewheres, an' there ain't any one but what says he's the town fool, all right."

   • 2010 July 16, Alessandra Stanley, "Television: Back to Work for ‘Mad Men’," New York Times (retrieved 16 June 2016):

     Pete Campbell (Vincent Kartheiser) would be just another irritating office brown-noser, a prep school Sammy Glick, except that he too has a screw loose and a mystical rapport with firearms.

• screwball
• screwy