Numbnuts American offensive slang
The phrase is derogatory, and sometimes humorous. It is often used as a term of address.
Used to say that somebody is an idiot or a stupid person
Don't ask him this question. He's such a numbnut.
Some numbnuts left the tap running in the bathroom and there's water everywhere.
Put your hand here, numbnut!
Extremely stupid
Very stupid, or silly
Stupid or crazy
(n): a fool person,
(adj): stupid, foolish, silly
He is rich but also stupid.
Green’s Dictionary of Slang traces the use of "numbnuts", meaning “idiot” when used as a term of address, back to 1969. The term is a natural evolution from the term "numb head", which has been in use since the 18th century.
Used to express something bad is happening again
Here we go again! Lisa has just asked to borrow my new dress.