What does Boxing Day have to do with boxing?
1919, "fellow, chap," from variant of Italian bambino "baby;" first attested in Italian-accented theater dialogue. Originally especially "stupid, inconsequential man, contemptible person;" by 1920 the sense of "floozie" had developed (popularized by "Variety" staffer Jack Conway, d.1928). Resurrection during 1980s U.S. political sex scandals led to derivatives including diminutive bimbette (1990) and male form himbo (1988).
[fr Italian, ''baby, bambino''; see babe]