What does the saying screw loose mean?
There is no saying called screw loose but there is one called have a screw loose which is the one you might be talking about.To have a screw loose means that you are not entirely in your right mind, or not entirely acting or thinking normally.Other idioms that mean essentially the same as "He has a few screws loose" are "He has bats in his belfry" (that's an old one), "He's not playing with a full deck", "He's not the brightest bulb on the Christmas tree" and "He's a few fries short of a Happy Meal." There are probably many others. -HW