bananas

[From banana, worthless or crazy person, from BANANA.]

adjective

Afflicted with or exhibiting irrationality and mental unsoundness: brainsick, crazy, daft, demented, disordered, distraught, dotty, insane, lunatic, mad, maniac, maniacal, mentally ill, moonstruck, off, touched, unbalanced, unsound, wrong. Informal bonkers, cracked, daffy, gaga, loony. Slang batty, buggy, cuckoo, fruity, loco, nuts, nutty, screwy, wacky. Chiefly British crackers. Law non compos mentis. Idioms: around the bend, crazy as a loon, mad as a hatter, not all there, nutty as a fruitcake, offout ofone's head, off one's rocker, of unsound mind, out of one's mind, sick in the head, stark raving mad. See sane/insane.