The Collaborative International Dictionary of English v.0.48:

Crush \Crush\ (kr[u^]sh), v. t. [imp. & p. p. Crushed
   (kr[u^]sht); p. pr. & vb. n. Crushing.] [OE. cruschen,
   crousshen, Of. cruisir, croissir, fr. LL. cruscire, prob. of
   Ger. origin, from a derivative of the word seen in Goth.
   kruistan to gnash; akin to Sw. krysta to squeeze, Dan.
   kryste, Icel. kreysta.]
   1. To press or bruise between two hard bodies; to squeeze, so
      as to destroy the natural shape or integrity of the parts,
      or to force together into a mass; as, to crush grapes.
      [1913 Webster]

            Ye shall not offer unto the Lord that which is
            bruised, or crushed, or broken, or cut. --Lev. xxii.
                                                  24.
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            The ass . . . thrust herself unto the wall, and
            crushed Balaam's foot against the wall. --Num. xxii.
                                                  25.
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   2. To reduce to fine particles by pounding or grinding; to
      comminute; as, to crush quartz.
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   3. To overwhelm by pressure or weight; to beat or force down,
      as by an incumbent weight.
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            To crush the pillars which the pile sustain.
                                                  --Dryden.
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            Truth, crushed to earth, shall rise again. --Bryant.
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   4. To oppress or burden grievously.
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            Thou shalt be only oppressed and crushed alway.
                                                  --Deut.
                                                  xxviii. 33.
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   5. To overcome completely; to subdue totally.
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            Speedily overtaking and crushing the rebels. --Sir.
                                                  W. Scott.
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   6. to subdue or overwhelm (a person) by argument or a cutting
      remark; to cause (a person) to feel chagrin or
      humiliation; to squelch.
      [PJC]

   To crush a cup, to drink. [Obs.]

   To crush out.
      (a) To force out or separate by pressure, as juice from
          grapes.
      (b) To overcome or destroy completely; to suppress.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Crushing \Crush"ing\, a.
   That crushes; overwhelming. "The blow must be quick and
   crushing." --Macualay.
   [1913 Webster]

WordNet (r) 3.0 (2006):

crushing
    adj 1: physically or spiritually devastating; often used in
           combination; "a crushing blow"; "a crushing rejection";
           "bone-crushing" [syn: crushing, devastating]
    n 1: forceful prevention; putting down by power or authority;
         "the suppression of heresy"; "the quelling of the
         rebellion"; "the stifling of all dissent" [syn:
         suppression, crushing, quelling, stifling]

Moby Thesaurus II by Grady Ward, 1.0:

42 Moby Thesaurus words for "crushing":
   Herculean, annoying, arduous, awkward, backbreaking, besetting,
   bothersome, burdensome, chastening, disconcerting, disturbing,
   effortful, embarrassing, forced, grueling, hard-earned,
   hard-fought, heavy, hefty, humbling, humiliating, humiliative,
   irksome, killing, labored, laborious, mortifying, onerous, operose,
   oppressive, painful, plaguey, punishing, strained, strenuous,
   toilsome, tough, troublesome, trying, uphill, vexatious,
   wearisome