A mimbo is a very good lookingmale who either is or acts like he is extremely stupid. The female counterpart of the mimbo is the bimbo.
Derek Zoolander from the movie Zoolander makes fun of an stereotypical mimbo - renowned for being "ridiculously good looking" yet having the brain cells of a gnat.
A man who is rather ditzy. The equivilent of a female bimbo or bambi. Not to be confused with mambo.
Maggie: OMG. Mitchell is such a mimbo!
Mary: I know! I can't believe he twirls his hair!
Liz: Remember when he ran into the door?
Noemi: And when he molested the Dough Boy?
*group laughs*