https://en.m.wikipedia.org/wiki/Bimbo
The word bimbo derives from the Italian bimbo, a masculine-gender term that means "little or baby boy" or "young (male) child" (the feminine form of the Italian word is bimba).
As bimbo began to be used increasingly for females, exclusively male variations of the word began to surface, like mimbo and himbo, a backformation of bimbo, which refers to an unintelligent, but attractive, man.
Bimbo is a vernacular word now regardless of origin and correct grammatical use.