Source : Webster's Revised Unabridged Dictionary (1913)

Knock-off \Knock"-off`\, n.
   Act or place of knocking off; that which knocks off; specif.
   (Mach.), a cam or the like for disconnecting something, as a
   device in a knitting machine to remove loops from the
   needles.

Knock-off \Knock"-off`\, a.
   That knocks off; of or pertaining to knocking off.