noun

• (usually now in the plural) One of the long, narrow feathers on the neck of birds, most noticeable on the rooster.
• (fishing) A feather used to make a fishing lure or a fishing lure incorporating a feather.
• (usually now in the plural) By extension (because the hackles of a rooster are lifted when it is angry), the hair on the nape of the neck in dogs and other animals; also used figuratively for humans.
  "When the dog got angry, his hackles rose and he growled."
• (uncountable, slang) Pluck; courage or energy.
  ""COME ALONG YE GRASS-COMBERS, SHOW some hackle," David Ingram, striding ahead, turned back and called."

verb

• (transitive) To separate, as the coarse part of flax or hemp from the fine, by drawing it through the teeth of a hackle or hatchel.
• (archaic, transitive) To tear asunder; to break into pieces.
  "the other divisions of the kingdom being hackled and torn to pieces"