The Collaborative International Dictionary of English v.0.48:

Stintless \Stint"less\, a.
   Without stint or restraint.
   [1913 Webster]

         The stintlesstears of old Heraclitus.    --Marston.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "stintless":
   bighearted, bounteous, bountiful, free, freehanded, freehearted,
   generous, giving, gracious, greathearted, handsome, hospitable,
   large, largehearted, lavish, liberal, magnanimous, munificent,
   open, openhanded, openhearted, princely, profuse, ungrudging,
   unselfish, unsparing, unstinted, unstinting