The Collaborative International Dictionary of English v.0.48:

Effete \Ef*fete"\, a. [L. effetus that has brought forth,
   exhausted; ex + fetus that has brought forth. See Fetus.]
   No longer capable of producing young, as an animal, or fruit,
   as the earth; hence, worn out with age; exhausted of energy;
   incapable of efficient action; no longer productive; barren;
   sterile.
   [1913 Webster]

         Effete results from virile efforts.      --Mrs.
                                                  Browning
   [1913 Webster]

         If they find the old governments effete, worn out, . .
         . they may seek new ones.                --Burke.
   [1913 Webster]

WordNet (r) 3.0 (2006):

effete
    adj 1: marked by excessive self-indulgence and moral decay; "a
           decadent life of excessive money and no sense of
           responsibility"; "a group of effete self-professed
           intellectuals" [syn: decadent, effete]

Moby Thesaurus II by Grady Ward, 1.0:

198 Moby Thesaurus words for "effete":
   ablated, all in, anemic, arid, asthenic, ausgespielt, barren, blah,
   blank, bleary, bloodless, bootless, burned-out, burnt up,
   characterless, chicken, cold, colorless, coming apart, consumed,
   counterproductive, cowardly, cracking, crumbling, dead,
   debilitated, decadent, decayed, decaying, declining, degenerate,
   depleted, deteriorating, devitalized, disabled, disintegrating,
   dismal, dissipated, dissolute, done, done in, done up, draggy,
   drained, draining, drearisome, dreary, drooping, droopy, dry,
   dryasdust, dull, dusty, dwindling, eaten up, ebbing, elephantine,
   emptied, empty, enervated, enfeebled, eroded, etiolated,
   eviscerated, exhausted, fade, fading, failing, faint, faintish,
   falling, far-gone, fatigued, fatuitous, fatuous, feckless, feeble,
   finished, flabby, flaccid, flagging, flat, floppy, fragmenting,
   frazzled, fruitless, futile, going to pieces, gone, gutless, heavy,
   ho-hum, hollow, imbecile, immoral, impotent, impoverished,
   inadequate, inane, incapacitated, ineffective, ineffectual,
   inefficacious, inexcitable, infecund, infertile, inoperative,
   insipid, invalid, jaded, jejune, laid low, languid, languishing,
   languorous, leaden, lifeless, limber, limp, listless, low-spirited,
   lustless, marcescent, marrowless, nerveless, nugacious, nugatory,
   of no force, out, overripe, pale, pallid, pedestrian, pining,
   pithless, played out, plodding, pointless, poky, ponderous, pooped,
   powerless, regressive, retrograde, retrogressive, rubbery,
   run-down, sapless, sapped, shotten, shriveling, sinewless, sinking,
   slack, sliding, slipping, slow, slumping, soft, solemn, spent,
   spineless, spiritless, sterile, stiff, stodgy, strengthless,
   stuffy, subsiding, superficial, tabetic, tasteless, tedious, tired,
   unavailing, unfruitful, unhardened, unlively, unnerved, unstrung,
   used up, useless, vain, vapid, waning, washed-out, wasted, wasting,
   weak, weakened, weakly, wilting, withering, wooden, worn,
   worn away, worn-out, worsening