Definition of "nutty"

Brown rice has had only its outer hull removed, leaving it with a beige color and a pleasantly nutty flavor.

1997, Mary Jo Plutt, Prevention's Stop Dieting and Lose Weight Cookbook, Rodale, page 210

Skinner's friendship with his nutty pals seemed to have come to a sudden end.

1932, Frank Richards, “The Complete Outsider”, in The Magnet