Box their ears - Idioms by The Free Dictionary
box (one's) ears (redirected from box their ears)
box (one's) ears
To hit someone. This now-outdated phrase is usually said as a vague threat. The next time you borrow my car without my permission, I'll box your ears!
box somebody’s ˈears,
give somebody a box on the ˈears (old-fashioned) hit somebody with your hand on the side of their head as a punishment: If you do that one more time I’ll box your ears, boy!