Source : Webster's Revised Unabridged Dictionary (1913)

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.

         An inexhaustible store of anecdotes.     --Macaulay.
   -- {In`ex*haust"i*ble*ness}, n. -- {In`ex*haust"i*bly}, adv.

Source : WordNet®

inexhaustibly
     adv : with indefatigable energy; "she watched the show
           indefatigably" [syn: {indefatigably}, {tirelessly}]