son of a gun

1 ENTRIES FOUND:
son of a gun noun
plural sons of guns
son of a gun
noun
plural sons of guns
Britannica Dictionary definition of SON OF A GUN
US, informal
1 
[count] : a person (especially a man) or thing that you are annoyed with
2 
old-fashioned — used by a man to address a male friend
3 
— used to express mild surprise, disappointment, etc.