Webster's Revised Unabridged Dictionary · 1913

knock off

knock off , noun

a device in a knitting machine to remove loops from the needles.

knock off , verb, intransitive and transitive

1.
to quit (working).
2.
to accomplish; -- frequently used when the task is accomplished rapidly.
3.
to kill; to defeat (opponents). [Colloquial]
4.
to discount, to deduct (a sum from a price).
5.
to rob.
6.
to make a knockoff of; to copy or imitate, usually without permission or admission of copying. — [MW10]

Knock-off , noun

1.
(Machinery) Act or place of knocking off; that which knocks off;
(Machinery) a cam or the like for disconnecting something, as a device in a knitting machine to remove loops from the needles.
2.

Knock-off , adjective

That knocks off; of or pertaining to knocking off.