son of a gun

noun

plural

sons of guns 

1. a 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?

interjection

1. (used as an exclamation of irritation, surprise, dismay, etc.)

son of a gun

noun

1. slang,  a rogue or rascal: used as a jocular form of address

Word History and Origins

Origin of son of a gun¹

First recorded in 1700–10; perhaps originally the illegitimate offspring of a soldier, though later influenced by British argot gun “thief”; gun moll