relentlessly

from WordNet (r) 3.0 (2006)

relentlessly
    adv 1: in a relentless manner; "he worked relentlessly" [syn:
           {relentlessly}, {unrelentingly}]

from The Collaborative International Dictionary of English v.0.48

Relentless \Re*lent"less\, a.
   Unmoved by appeals for sympathy or forgiveness; insensible to
   the distresses of others; destitute of tenderness;
   unrelenting; unyielding; unpitying; as, a prey to relentless
   despotism.
   [1913 Webster]

         For this the avenging power employs his darts, . . .
         Thus will persist, relentless in his ire. --Dryden.
   [1913 Webster] -- {Re*lent"less*ly}, adv. --
   {Re*lent"less*ness}, n.
   [1913 Webster]