godan verb (-ku), transitive verb
A forceful, often open-handed hit; can be used for slapping a face, spanking a child, or striking with a flat object. Colloquial and somewhat rough.
彼は怒って相手の顔をひっぱたいた。
He got angry and slapped the other person's face.
いたずらをした子供のお尻をひっぱたく。
I spank the bottom of the child who misbehaved.