Off one's nut:
Not in one's right mind, crazy, mad, confused.
Examples:
You can't do that! Are you off your nut or what?
Tom was declared 'Off His Nut' when he saw an alien steal his baby.
Meaning of nut from the English-Bulgarian dictionary:
Walnut, hazelnut, peanut, etc.
Learn English from home at a time convenient for you:
Learning system;- Video recordings from our system;
- Teachers' opinions and reviews;
- Free word learning tool.