The Collaborative International Dictionary of English v.0.48:

Arid \Ar"id\, a. [L. aridus, fr. arere to be dry: cf. F. aride.]
   Exhausted of moisture; parched with heat; dry; barren. "An
   arid waste." --Thomson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

arid
    adj 1: lacking sufficient water or rainfall; "an arid climate";
           "a waterless well"; "miles of waterless country to cross"
           [syn: arid, waterless]
    2: lacking vitality or spirit; lifeless; "a technically perfect
       but arid performance of the sonata"; "a desiccate romance";
       "a prissy and emotionless creature...settles into a mold of
       desiccated snobbery"-C.J.Rolo [syn: arid, desiccate,
       desiccated]

Moby Thesaurus II by Grady Ward, 1.0:

138 Moby Thesaurus words for "arid":
   Saharan, academic, acarpous, anhydrous, athirst, barren, blah,
   blank, bloodless, bone-dry, bookish, boring, bromidic, celibate,
   characterless, childless, cold, colorless, dead, desert, desolate,
   dismal, drab, draggy, drained, drearisome, dreary, dried-up,
   droughty, dry, dry as dust, dryasdust, dull, dusty, earthbound,
   effete, elephantine, empty, etiolated, exhausted, fade, fallow,
   flat, fruitless, gaunt, gelded, heavy, high and dry, ho-hum,
   hollow, humdrum, impotent, inane, ineffectual, inexcitable,
   infecund, infertile, insipid, issueless, jejune, juiceless,
   lackluster, leached, leaden, lifeless, like parchment, literal,
   low-spirited, menopausal, moistureless, monotonous, mundane,
   nonfertile, nonproducing, nonproductive, nonprolific, pale, pallid,
   pedantic, pedestrian, plodding, pointless, poky, ponderous,
   prosaic, prosing, prosy, sandy, sapless, sere, sine prole, slow,
   solemn, spiritless, staid, sterile, stiff, stodgy, stolid, stuffy,
   sucked dry, superficial, tasteless, tedious, teemless, thirsting,
   thirsty, unanimated, uncultivated, undamped, unfanciful, unfertile,
   unfruitful, unideal, unimaginative, uninspired, uninteresting,
   uninventive, unlively, unoriginal, unplowed, unpoetic,
   unproductive, unprolific, unromantic, unromanticized, unsown,
   untilled, unwatered, vapid, virgin, waste, wasted, waterless,
   weariful, wearisome, without issue, wooden