Source : Webster's Revised Unabridged Dictionary (1913)

Quenchless \Quench"less\, a.
   Incapable of being quenched; inextinguishable; as, quenchless
   fire or fury. ``Once kindled, quenchless evermore.'' --Byron.

   Syn: Inextinguishable; unquenchable. -- {Quench"less*ly},
        adv. -- {Quench"less*ness}, n.

Source : WordNet®

quenchless
     adj : impossible to quench; "unquenchable thirst" [syn: {unquenchable}]