The Collaborative International Dictionary of English v.0.48:

Squelch \Squelch\, n.
   1. A heavy fall, as of something flat.
      [1913 Webster]

   2. Hence: A crushing reply; as, the perfect squelch for a
      conceited remark. [Colloq.] --Hudibras.
      [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Squelch \Squelch\ (skw[e^]lch), v. i. [Perh. imitative. Cf.
   Squelch.]
   To make a sound like that made by the feet of one walking in
   mud or slush; to make a kind of swashing sound; to squish;
   also, to move with such a sound.
   [Webster 1913 Suppl.]

         He turned and strode to the fire, his boots squelching
         as he walked.                            --P. L. Ford.
   [Webster 1913 Suppl.]

         A crazy old collier squelching along under squared
         yards.                                   --W. C.
                                                  Russell.
   [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Squelch \Squelch\ (skw[e^]lch), v. t. [imp. & p. p. Squelched
   (skw[e^]lcht); p. pr. & vb. n. Squelching.] [Cf. Prov. E.
   quelch a blow, and quell to crush, to kill.]
   To quell; to crush; to silence or put down. [Colloq.]
   [1913 Webster]

         Oh 't was your luck and mine to be squelched. --Beau. &
                                                  Fl.
   [1913 Webster]

         If you deceive us you will be squelched. --Carlyle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

squelch
    n 1: a crushing remark [syn: put-down, squelch, squelcher,
         takedown]
    2: an electric circuit that cuts off a receiver when the signal
       becomes weaker than the noise [syn: squelch circuit,
       squelch, squelcher]
    v 1: suppress or crush completely; "squelch any sign of
         dissent"; "quench a rebellion" [syn: squelch, quell,
         quench]
    2: make a sucking sound
    3: walk through mud or mire; "We had to splosh across the wet
       meadow" [syn: squelch, squish, splash, splosh,
       slosh, slop]
    4: to compress with violence, out of natural shape or condition;
       "crush an aluminum can"; "squeeze a lemon" [syn: squash,
       crush, squelch, mash, squeeze]

Moby Thesaurus II by Grady Ward, 1.0:

168 Moby Thesaurus words for "squelch":
   answer, answer conclusively, argue down, asphyxiate, assibilate,
   assibilation, barb, black out, bottle up, buzz, censor, choke,
   choke off, clamp down on, comeback, complete answer, confound,
   confounding, confutation, confute, contradict, contradiction,
   controversion, controvert, cork, cork up, crack down on, crush,
   damp down, defeat, demolish, demolition, denial, deny,
   discrediting, dismiss, dispose of, drown, dumbfound,
   effective rejoinder, effervesce, effervescence, effervescing,
   extinguish, finish, fizz, fizzle, fizzling, floor, frication,
   frictional rustling, gag, gibe, hiss, hissing, hold down,
   hugger-mugger, humiliate, hush, hush up, hush-hush, hushing, jibe,
   jump on, keep down, keep under, kill, lisp, muffle, muzzle,
   nonplus, outdo, overcome, overthrow, overthrowal, overturn,
   overwhelm, parry, pour water on, put down, put out, put to silence,
   put-down, quash, quell, quench, quiet, quieten, quip, rebut,
   rebuttal, reduce to silence, refutal, refutation, refute, repress,
   retort, rhonchus, riposte, sally, settle, shoot down, shush,
   shushing, shut down on, shut up, sibilance, sibilate, sibilation,
   siffle, sigmatism, silence, siss, sissing, sit down on, sit on,
   sizz, sizzle, sizzling, smash, smash all opposition, smother,
   sneeze, sneezing, sniff, sniffle, snore, snort, snuff, snuff out,
   snuffle, soft-pedal, spit, splutter, sputter, squash, squish,
   stamp out, stanch, sternutation, stertor, stifle, still, strangle,
   strike dumb, stultify, subdue, subversion, subvert, suffocate,
   suppress, swish, throttle, trample out, trample underfoot,
   undermine, undermining, upset, upsetting, wheeze, whish, whistle,
   whistling, white noise, whiz, whoosh, wisecrack, zip