Source : Webster's Revised Unabridged Dictionary (1913)

Bristle \Bris"tle\, v. i.
   1. To rise or stand erect, like bristles.

            His hair did bristle upon his head.   --Sir W.
                                                  Scott.

   2. To appear as if covered with bristles; to have standing,
      thick and erect, like bristles.

            The hill of La Haye Sainte bristling with ten
            thousand bayonets.                    --Thackeray.

            Ports bristling with thousands of masts. --Macaulay.

   3. To show defiance or indignation.

   {To bristle up}, to show anger or defiance.