A synonym for one's limbs attached to their shoulder. This term (deriving from the recently synonymized word for foot, i.e. dog) is often used in a demeaning tone.
In a literal sense it means they could hold a duel or could easily have a one on one gentleman’s fist fight.
What it actually means is that two things are equal in measure to such a point that they might need to resort to drastic measures in order to change one’s perception.