The Collaborative International Dictionary of English v.0.48:

Inexhaustible \In`ex*haust"i*ble\, a.
   Incapable of being exhausted, emptied, or used up; unfailing;
   not to be wasted or spent; as, inexhaustible stores of
   provisions; an inexhaustible stock of elegant words.
   --Dryden.
   [1913 Webster]

         An inexhaustible store of anecdotes.     --Macaulay.
   -- In`ex*haust"i*ble*ness, n. -- In`ex*haust"i*bly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inexhaustible
    adj 1: that cannot be entirely consumed or used up; "an
           inexhaustible supply of coal" [syn: inexhaustible,
           unlimited]
    2: incapable of being entirely consumed or used up; "an
       inexhaustible supply of coal" [ant: exhaustible]

Moby Thesaurus II by Grady Ward, 1.0:

110 Moby Thesaurus words for "inexhaustible":
   abounding, abundant, affluent, all-comprehensive, all-inclusive,
   all-sufficing, ample, aplenty, bottomless, boundless, bounteous,
   bountiful, copious, countless, diffuse, effuse, endless, epidemic,
   eternal, exhaustless, extending everywhere, extravagant, exuberant,
   fat, fertile, flush, full, galore, generous, illimitable,
   illimited, immeasurable, immense, in plenty, in quantity,
   incalculable, incomprehensible, indefatigable, indeterminate,
   infinite, infinitely continuous, innumerable, interminable,
   interminate, lavish, liberal, limitless, luxuriant, many, maximal,
   measureless, much, no end of, numberless, numerous, opulent,
   overflowing, perpetual, plenitudinous, plenteous, plentiful,
   plenty, prevailing, prevalent, prodigal, productive, profuse,
   profusive, rampant, replete, rich, rife, riotous, running over,
   shoreless, sumless, superabundant, teeming, termless, tireless,
   unbounded, uncircumscribed, uncounted, unfailing, unfaltering,
   unfathomable, unflagging, universal, unlimited, unmeasurable,
   unmeasured, unnumbered, unplumbed, unrestricted, untiring, untold,
   unwearied, unwearying, wealthy, weariless, well-found,
   well-furnished, well-provided, well-stocked, wholesale,
   without bound, without end, without limit, without measure,
   without number