WordNet (r) 3.0 (2006):

straightjacket
    n 1: a garment similar to a jacket that is used to bind the arms
         tightly against the body as a means of restraining a
         violent person [syn: straitjacket, straightjacket]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "straightjacket":
   Oregon boat, bilbo, bond, bonds, bridle, camisole, chains, collar,
   cuffs, fetter, gag, gyves, halter, hamper, handcuffs, hobbles,
   hopples, irons, leading strings, leash, manacle, muzzle, pillory,
   reins, restraint, restraints, shackle, stocks, strait-waistcoat,
   straitjacket, stranglehold, tether, trammel, trammels, yoke