1.a man who is the lover of a girl or young woman;
2.a boy or man;
3.a person who is member of your class or profession;
4.a person who is frequently in the company of another;
5.an informal form of address for a man;
1."if I'd known he was her boyfriend I wouldn't have asked"
2."that chap is your host"; "there's a fellow at the door"; "he's a likable cuss"
3."the surgeon consulted his colleagues"; "he sent e-mail to his fellow hackers"
4."drinking companions"; "comrades in arms"
5."Say, fellow, what are you doing?"; "Hey buster, what's up?"