knock

knock is a Verb

Definition:

[1] To drive or be driven against something; to strike against something; to clash; as, one heavy body knocks against another. Bacon.

[2] To strike or beat with something hard or heavy; to rap; as, to knock with a club; to knock on the door. For harbor at a thousand doors they knocked. Dryden. Seek, and ye shall find; knock, and it shall be opened unto you. Matt. vii. 7. To knock about, to go about, taking knocks or rough usage; to wander about; to saunter. [Colloq.] "Knocking about town." W. Irving. -- To knock up, to fail of strength; to become wearied or worn out, as with labor; to give out. "The horses were beginning to knock up under the fatigue of such severe service." De Quincey. -- To knock off, to cease, as from work; to desist. -- To knock under, to yield; to submit; to acknowledge one`s self conquered; -- an expression probably borrowed from the practice of knocking under the table with the knuckles, when conquered. "Colonel Esmond knocked under to his fate." Thackeray.