The story
From the idea that police officers might knock in this way.
Etymology from Wiktionary, CC BY-SA 4.0.
cop knock
Today it means: A loud, hard knock at a door. Full definition →
Today it means: A loud, hard knock at a door. Full definition →
From the idea that police officers might knock in this way.
Etymology from Wiktionary, CC BY-SA 4.0.