The Collaborative International Dictionary of English v.0.48:

Bridle \Bri"dle\, n. [OE. bridel, AS. bridel; akin to OHG.
   britil, brittil, D. breidel, and possibly to E. braid. Cf.
   Bridoon.]
   1. The head gear with which a horse is governed and
      restrained, consisting of a headstall, a bit, and reins,
      with other appendages.
      [1913 Webster]

   2. A restraint; a curb; a check. --I. Watts.
      [1913 Webster]

   3. (Gun.) The piece in the interior of a gun lock, which
      holds in place the tumbler, sear, etc.
      [1913 Webster]

   4. (Naut.)
      (a) A span of rope, line, or chain made fast as both ends,
          so that another rope, line, or chain may be attached
          to its middle.
      (b) A mooring hawser.
          [1913 Webster]

   Bowline bridle. See under Bowline.

   Branches of a bridle. See under Branch.

   Bridle cable (Naut.), a cable which is bent to a bridle.
      See 4, above.

   Bridle hand, the hand which holds the bridle in riding; the
      left hand.

   Bridle path, Bridle way, a path or way for saddle horses
      and pack horses, as distinguished from a road for
      vehicles.

   Bridle port (Naut.), a porthole or opening in the bow
      through which hawsers, mooring or bridle cables, etc., are
      passed.

   Bridle rein, a rein attached to the bit.

   Bridle road.
      (a) Same as Bridle path. --Lowell.
      (b) A road in a pleasure park reserved for horseback
          exercise.

   Bridle track, a bridle path.

   Scolding bridle. See Branks, 2.
      [1913 Webster]

   Syn: A check; restrain.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Bridle \Bri"dle\, v. i.
   To hold up the head, and draw in the chin, as an expression
   of pride, scorn, or resentment; to assume a lofty manner; --
   usually with up. "His bridling neck." --Wordsworth.
   [1913 Webster]

         By her bridling up I perceived she expected to be
         treated hereafter not as Jenny Distaff, but Mrs.
         Tranquillus.                             --Tatler.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Bridle \Bri"dle\, v. t. [imp. & p. p. Bridled; p. pr. & vb. n.
   Bridling.]
   1. To put a bridle upon; to equip with a bridle; as, to
      bridle a horse.
      [1913 Webster]

            He bridled her mouth with a silkweed twist. --Drake.
      [1913 Webster]

   2. To restrain, guide, or govern, with, or as with, a bridle;
      to check, curb, or control; as, to bridle the passions; to
      bridle a muse. --Addison.
      [1913 Webster]

            Savoy and Nice, the keys of Italy, and the citadel
            in her hands to bridle Switzerland, are in that
            consolidation.                        --Burke.
      [1913 Webster]

   Syn: To check; restrain; curb; govern; control; repress;
        master; subdue.
        [1913 Webster]

WordNet (r) 3.0 (2006):

bridle
    n 1: headgear for a horse; includes a headstall and bit and
         reins to give the rider or driver control
    2: the act of restraining power or action or limiting excess;
       "his common sense is a bridle to his quick temper" [syn:
       bridle, check, curb]
    v 1: anger or take offense; "She bridled at his suggestion to
         elope"
    2: put a bridle on; "bridle horses" [ant: unbridle]
    3: respond to the reins, as of horses

Moby Thesaurus II by Grady Ward, 1.0:

193 Moby Thesaurus words for "bridle":
   Oregon boat, anchor, anger, arrest, back band, backstrap,
   bearing rein, bed, bed down, bellyband, bilbo, bind, bit, blinders,
   blinds, boil over, bond, bonds, break, breeching, bridle up,
   bristle, bristle up, brush, camisole, caparison, cavesson, chain,
   chains, check, checkrein, cheekpiece, chinband, cinch, collar,
   condescend, constrain, contain, control, cool, cool off, crownband,
   crupper, cuffs, curb, curry, currycomb, curtail, deal with,
   decelerate, dompt, drench, enchain, enjoin, entrammel, fasten,
   feed, fetter, flip out, fodder, gag, gag swivel, gentle, get mad,
   get sore, girth, govern, groom, guard, gyve, gyves, hackamore,
   halter, hames, hametugs, hamper, handcuff, handcuffs, handle,
   harness, headgear, headstall, hinder, hip straps, hitch, hitch up,
   hobble, hobbles, hog-tie, hold, hold at bay, hold back, hold down,
   hold fast, hold in, hold in check, hold in leash, hold up, hook up,
   hopple, hopples, inhibit, irons, jaquima, jerk line, keep,
   keep back, keep from, keep in, keep in check, keep under control,
   lash, lay under restraint, leading strings, leash, lines, litter,
   make fast, manacle, manage, martingale, milk, mince, mince it,
   moor, muzzle, noseband, patronize, peg down, picket, pillory,
   pin down, pinion, pole strap, prink, prohibit, pull, pull in,
   put in irons, reach boiling point, rein, rein in, reins, repress,
   restrain, restraint, restraints, retard, retrench, ribbons, rope,
   rub down, rule, saddle, secure, see red, set back, shackle,
   shaft tug, side check, simper, slow down, smirk, snaffle, snub,
   stocks, straightjacket, strait-waistcoat, straiten, straitjacket,
   stranglehold, strap, suppress, surcingle, tack, tackle, tame, tend,
   tether, tie, tie down, tie up, toss the head, train, trammel,
   trammels, trappings, treat, tug, water, winker braces, withhold,
   yoke



Easton's 1897 Bible Dictionary:

Bridle
   Three Hebrew words are thus rendered in the Authorized Version.
   (1.) Heb. _mahsom'_ signifies a muzzle or halter or bridle, by
   which the rider governs his horse (Ps.39:1).

     (2.) _Me'theg_, rendered also "bit" in Ps. 32:9, which is its
   proper meaning. Found in 2 Kings 19:28, where the restraints of
   God's providence are metaphorically styled his "bridle" and
   "hook." God's placing a "bridle in the jaws of the people" (Isa.
   30:28; 37:29) signifies his preventing the Assyrians from
   carrying out their purpose against Jerusalem.

     (3.) Another word, _re'sen_, was employed to represent a
   halter or bridle-rein, as used Ps. 32:9; Isa. 30:28. In Job
   30:11 the restraints of law and humanity are called a bridle.