oh, boy!

noun

1. a male child from birth to the age of physical maturity; lad; youth
2. a man regarded as immature or callow
3. any man; fellow: familiar term
4. a male domestic worker or servant: a patronizing term applied esp. by Caucasians to nonwhites
5. a bellboy, messenger boy, etc.
6. Informal a son: Mrs. Dill's oldest boy

interjection