son of a gun: Meaning and Definition of

son' of a gun'

1. rogue; rascal; scoundrel: That son of a gun still owes me $20.
2. a tiresome or disagreeable matter, chore, etc.
3. (used as an affectionate greeting, term of address, etc.): Charlie Humpelmeyer, you old son of a gun, how are you?
4. (used as an exclamation of irritation, surprise, dismay, etc.).