The Collaborative International Dictionary of English v.0.48:

Sterile \Ster"ile\, a. [F. st['e]rile, L. sterilis, akin to Gr.
   stereo`s stiff, solid, stei^ros barren, stei^ra a cow that
   has not calved, Goth. stair[=o], fem., barren. See Stare to
   gaze.]
   1. Producing little or no crop; barren; unfruitful;
      unproductive; not fertile; as, sterile land; a sterile
      desert; a sterile year.
      [1913 Webster]

   2. (Biol.)
      (a) Incapable of reproduction; unfitted for reproduction
          of offspring; not able to germinate or bear fruit;
          unfruitful; as, a sterile flower, which bears only
          stamens.
      (b) Free from reproductive spores or germs; as, a sterile
          fluid.
          [1913 Webster]

   3. Fig.: Barren of ideas; destitute of sentiment; as, a
      sterile production or author.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sterile
    adj 1: incapable of reproducing; "an infertile couple" [syn:
           sterile, unfertile, infertile] [ant: fertile]
    2: free of or using methods to keep free of pathological
       microorganisms; "a sterile operating area"; "aseptic surgical
       instruments"; "aseptic surgical techniques" [syn: aseptic,
       sterile]
    3: deficient in originality or creativity; lacking powers of
       invention; "a sterile ideology lacking in originality";
       "unimaginative development of a musical theme"; "uninspired
       writing" [syn: sterile, unimaginative, uninspired,
       uninventive]

Moby Thesaurus II by Grady Ward, 1.0:

137 Moby Thesaurus words for "sterile":
   abortive, acarpous, antiseptic, arid, aseptic, bare, barren, blah,
   blank, bloodless, boiled, bootless, celibate, characterless,
   childless, cold, colorless, counterproductive, dead,
   decontaminated, desert, desolate, disinfected, dismal, draggy,
   drained, drearisome, dreary, dried-up, dry, dryasdust, dull, dusty,
   effete, elephantine, empty, etiolated, exhausted, fade, fallow,
   fatuitous, fatuous, feckless, flat, fruitless, futile, gainless,
   gaunt, gelded, heavy, ho-hum, hollow, hygienic, impotent,
   inadequate, inane, ineffective, ineffectual, inefficacious,
   inexcitable, infecund, infertile, inoperative, insipid, invalid,
   issueless, jejune, leached, leaden, lifeless, low-spirited,
   menopausal, noncreative, nonfertile, nonproducing, nonproductive,
   nonprolific, nonremunerative, nugacious, nugatory, of no force,
   otiose, pale, pallid, pasteurized, pedestrian, plodding, pointless,
   poky, ponderous, profitless, prophylactic, pure, rewardless,
   sanitary, sine prole, slow, solemn, spiritless, stale, sterilized,
   stiff, stodgy, stuffy, sucked dry, superficial, tasteless, tedious,
   teemless, unavailing, uncontaminated, uncreative, uncultivated,
   unfertile, unfruitful, uninfected, uninspired, uninventive,
   unlively, unplowed, unpolluted, unproductive, unprofitable,
   unprolific, unremunerative, unrewarding, unsown, untilled, useless,
   vain, vapid, virgin, waste, wasted, without issue, wooden,
   worn-out