This term for a floozie or loose woman, especially one of low intelligence, is from the Italian bambino, or baby. It makes its English appearance in 1918, in Rosano’s Price of Honor in a bit of Italian-accented dialogue:
She flop! An’ il bimbo he break da boni.
The original meaning was a stupid, inconsequential, or contemptible person. By 1920 the floozie sense had developed. From Zeidman’s Burlesque (1920):
This Dix bimbo is a dangerous woman...a sassy girl with...more than a figure—a physique.1
1Historical Dictionary of American Slang, v. 1, A-G, edited by Jonathan Lighter (New York: Random House, 1994), 159.
Copyright 1997-2017, by David Wilton