Beside being used as an Adjective to refer a male who act like gay or his homosexuality, I’ve heard quite a few male bankers called their female superiors “ Fruitcake”.... They're referring their female superiors look pretty and sweet, but nothing in their brain. It’s an insulting chauvinist way of belittling women’s ability at workplace.
Male Banker A: She didn't approve this half-million loan and client went to our competitor. Can't beleive she's so into those risk management thingy. We need sales!
Male Banker B: Told ya, I always wodering about how did she get her banking licence. She's tatotally a "fruitcake"!