The Collaborative International Dictionary of English v.0.48:

Harsh \Harsh\ (h[aum]rsh), a. [Compar. Harsher
   (h[aum]rsh"[~e]r); superl. Harshest.] [OE. harsk; akin to
   G. harsch, Dan. harsk rancid, Sw. h[aum]rsk; from the same
   source as E. hard. See Hard, a.]
   1. Rough; disagreeable; grating; esp.:
      (a) disagreeable to the touch. "Harsh sand." --Boyle.
      (b) disagreeable to the taste. "Berries harsh and crude."
          --Milton.
      (c) disagreeable to the ear. "Harsh din." --Milton.
          [1913 Webster]

   2. Unpleasant and repulsive to the sensibilities; austere;
      crabbed; morose; abusive; abusive; severe; rough.
      [1913 Webster]

            Clarence is so harsh, so blunt.       --Shak.
      [1913 Webster]

            Though harsh the precept, yet the preacher charmed.
                                                  --Dryden.
      [1913 Webster]

   3. (Painting, Drawing, etc.) Having violent contrasts of
      color, or of light and shade; lacking in harmony.
      [1913 Webster]

WordNet (r) 3.0 (2006):

harsh
    adj 1: unpleasantly stern; "wild and harsh country full of hot
           sand and cactus"; "the nomad life is rough and hazardous"
           [syn: harsh, rough]
    2: disagreeable to the senses; "the harsh cry of a blue jay";
       "harsh cognac"; "the harsh white light makes you screw up
       your eyes"; "harsh irritating smoke filled the hallway"
    3: of textures that are rough to the touch or substances
       consisting of relatively large particles; "coarse meal";
       "coarse sand"; "a coarse weave" [syn: coarse, harsh]
       [ant: fine]
    4: unkind or cruel or uncivil; "had harsh words"; "a harsh and
       unlovable old tyrant"; "a rough answer" [syn: harsh,
       rough]
    5: severe; "a harsh penalty"
    6: sharply disagreeable; rigorous; "the harsh facts of court
       delays"; "an abrasive character" [syn: harsh, abrasive]

Moby Thesaurus II by Grady Ward, 1.0:

333 Moby Thesaurus words for "harsh":
   Doric, Draconian, Spartan, Spartanic, abrupt, absonant, abusive,
   acerb, acerbic, acid, acidulous, acrid, acrimonious, acute,
   afflictive, aggressive, agonizing, ajar, amaroidal, asperous,
   astringent, atonal, atrocious, austere, authoritarian, barbaric,
   barbarous, bearish, beastly, bilious, biting, bitter,
   bitter as gall, blaring, bleak, bluff, blunt, blurred, bowelless,
   brash, brassy, brazen, breathy, bristly, brusque, brutal, brutish,
   burdensome, burning, cacophonous, caustic, cavalier, choked,
   choking, choleric, churlish, clashing, clumsy, coarse, colliding,
   comfortless, conflicting, confused, corrugated, cracked, cragged,
   craggy, cramping, crinkled, croaking, croaky, cross, crude, cruel,
   crumpled, crusty, curt, cutting, demanding, diaphonic,
   disagreeable, discomforting, disconsonant, discordant,
   discourteous, disharmonic, disharmonious, dissonant, distressing,
   dog-eat-dog, doggerel, double-edged, dour, drawling, drawly, dry,
   dysphemistic, dysphonic, ear-piercing, edged, escharotic, exacting,
   excruciating, exhausting, exigent, fierce, flat, flinty, gnawing,
   graceless, granular, grating, grave, gravelly, grim, grinding,
   griping, gross, grouchy, gruff, guttural, hairy, hard, harrowing,
   harsh-sounding, hawking, heartless, heavy, hoarse, hurtful,
   hurting, husky, immelodious, impolite, improper, impure,
   in bad taste, inarticulate, incisive, inclement, inconcinnate,
   inconcinnous, incongruous, incorrect, indecorous, indistinct,
   inelegant, inexorable, infelicitous, inharmonic, inharmonious,
   inhuman, intemperate, irascible, ironbound, irritating, jagged,
   jaggy, jangling, jangly, jarring, jostling, keen, lisping, loose,
   low, merciless, metallic, meticulous, mispronounced, mordacious,
   mordant, musicless, muzzy, nasal, nasty, nonmelodious,
   nose-tickling, off, off-color, off-key, off-tone, onerous,
   oppressive, out of pitch, out of tone, out of tune, outlandish,
   overburdensome, painful, paroxysmal, peevish, penetrating,
   petulant, piercing, piquant, pitiless, poignant, pungent,
   punishing, punitive, quavering, racking, ragged, rasping, raucid,
   raucous, relentless, remorseless, rigorous, rockbound, rocky,
   rough, roupy, rude, rugged, rugose, rugous, rusty, ruthless,
   sarcastic, saw-toothed, sawtooth, scabrous, scathing, scragged,
   scraggly, scraggy, scraping, scratchy, serrate, serrated, severe,
   shaggy, shaking, shaky, sharp, shooting, short, short-tempered,
   shrill, snagged, snaggled, snaggy, snippy, snuffling, sour,
   spasmatic, spasmic, spasmodic, splenetic, squawking, squawky,
   squeaky, stabbing, stark, stern, stertorous, stifled, stinging,
   stony, strangled, strict, strident, stridulous, stringent, stubbly,
   sullen, surly, tangy, tart, tasteless, thick, throaty, tinny,
   tormenting, torturous, tough, tremulous, trenchant, truculent,
   tuneless, twangy, tyrannical, tyrannous, uncivil, uncompassionate,
   uncompassioned, uncourtly, uncouth, undignified, uneuphonious,
   uneven, unfeeling, unfelicitous, unforgiving, unfriendly, ungentle,
   ungraceful, unharmonious, unkind, unlevel, unmelodious, unmerciful,
   unmusical, unpitiful, unpitying, unpleasant, unpolished, unrefined,
   unremorseful, unseemly, unsmooth, unsparing, unsympathetic,
   unsympathizing, untunable, untuned, untuneful, unyielding,
   vehement, velar, violent, virulent, vitriolic, vulgar, warring,
   waspish, wearing, wearying, weighty, without mercy, wrinkled