WordNet (r) 3.0 (2006):

hold down
    v 1: keep; "She manages to hold down two jobs"
    2: restrain; "please hold down the noise so that the neighbors
       can sleep"

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "hold down":
   asphyxiate, bit, bottle up, bridle, censor, check, choke off,
   clamp down on, constrain, cork, cork up, crack down on, crush,
   curb, damp down, deprive of freedom, disenfranchise, disfranchise,
   dominate, drown, enslave, enthrall, extinguish, gag, hold back,
   hold captive, hold in, hold in bondage, hold in captivity,
   hold in leash, hold in subjection, inhibit, jump on, keep down,
   keep under, kill, lead captive, make dependent, muzzle, peonize,
   pour water on, put down, quash, quell, quench, repress,
   shut down on, silence, sit down on, sit on, smash, smother, squash,
   squelch, stanch, stifle, strangle, stultify, subdue, subject,
   subjugate, subordinate, suffocate, suppress, take captive,
   throttle, vassalize, withhold