What does "knap" mean?

Knap: To bite; to bite off; to break short. [Obs. or Prov. Eng. ] He will knap the spears apieces with his teeth. Dr. H. More. He breaketh the bow, and knappeth the spear in sunder. Ps. xlvi. 9 (Book of Common Prayer.)

Additional senses

  1. 2.To strike smartly; to rap; to snap. Bacon.
  2. 3.To make a sound of snapping. Wiseman.
  3. 4.A sharp blow or slap. Halliwell.

Sources