no-knock

[ noh-nok ]
/ ˈnoʊˌnɒk /

adjective

Law. that authorizes law-enforcement officers to enter premises unannounced and without identifying themselves: a no-knock narcotics policy.

Origin of no-knock

An Americanism dating back to 1965–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019