The Collaborative International Dictionary of English v.0.48:

Gaunt \Gaunt\, a. [Cf. Norw. gand a thin pointed stick, a tall
   and thin man, and W. gwan weak.]
   Attenuated, as with fasting or suffering; lean; meager;
   pinched and grim. "The gaunt mastiff." --Pope.
   [1913 Webster]

         A mysterious but visible pestilence, striding gaunt and
         fleshless across our land.               --Nichols.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gaunt
    adj 1: very thin especially from disease or hunger or cold;
           "emaciated bony hands"; "a nightmare population of gaunt
           men and skeletal boys"; "eyes were haggard and
           cavernous"; "small pinched faces"; "kept life in his
           wasted frame only by grim concentration" [syn: bony,
           cadaverous, emaciated, gaunt, haggard, pinched,
           skeletal, wasted]

Moby Thesaurus II by Grady Ward, 1.0:

89 Moby Thesaurus words for "gaunt":
   acarpous, angular, arid, bare, barren, bleak, bony, cadaverous,
   celibate, childless, desert, deserted, desolate, dismal, drained,
   dreary, dried-up, dry, emaciated, exhausted, fallow, flat,
   flat-chested, fleshless, forbidding, forlorn, fruitless, gangling,
   gangly, gawky, gelded, grim, haggard, harsh, hostile, impotent,
   ineffectual, infecund, infertile, inimical, issueless, jejune,
   lank, lanky, leached, lean, lean-fleshed, lean-looking, meager,
   menopausal, nonfertile, nonproducing, nonproductive, nonprolific,
   pinched, rawboned, scraggy, scrawny, sine prole, skeletal, skinny,
   spare, spidery, spindling, spindly, stark, sterile, stern,
   sucked dry, teemless, thin, thin-bellied, thin-fleshed, twiggy,
   uncultivated, undersized, underweight, unfertile, unfriendly,
   unfruitful, unplowed, unproductive, unprolific, unsown, untilled,
   virgin, waste, wasted, without issue