mer·ci·less /ˈmɝsɪləs/
  (a.)無慈悲心的,殘忍的
  Mer·ci·less, a. Destitute of mercy; cruel; unsparing; -- said of animate beings, and also, figuratively, of things; as, a merciless tyrant; merciless waves.
     The foe is merciless, and will not pity.   --Shak.
  Syn: -- Cruel; unmerciful; remorseless; ruthless; pitiless; barbarous; savage.
  -- Mer*ci*less*ly, adv. -- Mer*ci*less*ness, n.
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  merciless
       adj : having or showing no mercy; "the merciless enemy"; "a
             merciless critic"; "gave him a merciless beating" [syn:
              unmerciful] [ant: merciful]