old-fashioned slang A derogatory and offensive term for a psychiatric hospital or insane asylum. A play on the slang term "nuts," meaning "crazy," and the actual meaning of "nuttery," a copse of nut-bearing trees. My great aunt Lidia apparently got locked up in a nuttery when she was a teenager because she said she could commune with ghosts. I can't go to the police about it! They'd throw me in the nuttery if I came to them with such an unbelievable story.