Definition of Beau

Noun: beau (beaux,beaus) bow

A man who is the lover of a girl or young woman
"if I'd known he was her beau I wouldn't have asked";
- boyfriend, fellow, swain [archaic], young man
A man who is much concerned with his dress and appearance
- dandy, dude, fop, gallant, sheik, swell, fashion plate, clotheshorse