(as) nutty as a fruitcake
01
かなり変わっている, 風変わり
(of a person) crazy or exhibiting odd behavior
idiom
例
After staying up for days working on his novel, John started seeing imaginary characters. He's been as nutty as a fruitcake lately.
あの山に一人で登るなんて、彼は相当変わっているに違いない。
