Definition
By the skin at the back of the neck, often used to indicate a forceful or rough way of moving or controlling someone or something.
The guard grabbed the thief by the scruff of his neck and dragged him out of the store.
She grabbed her son by the scruff of the neck and pulled him away from the fight.
He was almost late, so he grabbed his briefcase by the scruff of its neck and lifted it off the ground.