Source : Webster's Revised Unabridged Dictionary (1913)

Bristle \Bris"tle\ (br[i^]s"s'l), n. [OE. bristel, brustel, AS.
   bristl, byrst; akin to D. borstel, OHG. burst, G. borste,
   Icel. burst, Sw. borst, and to Skr. bh[.r]shti edge, point,
   and prob, L. fastigium extremity, Gr. 'a`flaston stern of a
   ship, and E. brush, burr, perh. to brad. [root]96.]
   1. A short, stiff, coarse hair, as on the back of swine.

   2. (Bot.) A stiff, sharp, roundish hair. --Gray.

Bristle \Bris"tle\, v. t. [imp. & p. p. {Bristled}; p. pr. & vb.
   n. {Bristling}.]
   1. To erect the bristles of; to cause to stand up, as the
      bristles of an angry hog; -- sometimes with up.

            Now for the bare-picked bone of majesty Doth dogged
            war bristle his angry crest.          --Shak.

            Boy, bristle thy courage up.          --Shak.

   2. To fix a bristle to; as, to bristle a thread.

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.

Source : WordNet®

bristle
     v 1: be in a state of movement or action; "The room abounded with
          screaming children"; "The garden bristled with toddlers"
          [syn: {abound}, {burst}]
     2: rise up as in fear; "The dog's fur bristled"; "It was a
        sight to make one's hair uprise!" [syn: {uprise}, {stand
        up}]

bristle
     n 1: a stiff fiber (coarse hair or filament); natural or
          synthetic
     2: a stiff hair