off (one's) nut(redirected from off my nut)
off (one's) nut
Crazy or insane. I think you're off your nut for changing careers this late in life, but, hey, follow your dreams. He's off his nut if he thinks he can get that engine fixed by this weekend.
off your nutout of your mind; crazy. informal
ˌoff your ˈnut(British English, informal, spoken) crazy: Is he completely off his nut?
Nut is an informal word for your head.