pitilessly

from WordNet (r) 3.0 (2006)

pitilessly
    adv 1: without pity; in a merciless manner; "he was mercilessly
           trounced by his opponent in the House" [syn:
           {mercilessly}, {pitilessly}, {unmercifully},
           {remorselessly}]

from The Collaborative International Dictionary of English v.0.48

Pitiless \Pit"i*less\, a.
   1. Destitute of pity; hard-hearted; merciless; as, a
      pitilessmaster; pitiless elements.
      [1913 Webster]

   2. Exciting no pity; as, a pitiless condition.
      [1913 Webster] -- {Pit"i*less*ly}, adv. --
      {Pit"i*less*ness}, n.
      [1913 Webster]