" mercilessly "

1: as in ruthlessly, callously;

•  Synonyms : 

•  callously,

•  cold-bloodedly,

•  hard-heartedly,

•  heartlessly,

•  inhumanely,

•  inhumanly,

•  insensately,

•  insensitively,

•  obdurately,

•  pitilessly,

•  ruthlessly,

•  tyrannically,

•  uncharitably,

•  unfeelingly,

•  unmercifully,

•  unsparingly,

•  brutally,

•  hard,

•  hardly,

•  harshly,

•  ill,

•  oppressively,

•  roughly,

•  severely,

•  sternly,

•  stiffly,

•  abusively,

•  brutishly,

•  savagely,

•  viciously,

•  aggressively,

•  assertively,

•  decidedly,

•  determinedly,

•  firmly,

•  grimly,

•  gruffly,

•  resolutely,

•  strongly,

•  toughly

•  Antonyms : 

•  clemently,

•  gently,

•  leniently,

•  lightly,

•  mildly,

•  softly,

•  benevolently,

•  benignantly,

•  considerately,

•  cordially,

•  graciously,

•  kindly,

•  lovingly,

•  tenderly,

•  charitably,

•  compassionately,

•  humanely,

•  mercifully,

•  softheartedly,

•  sympathetically,

•  tolerantly,

•  understandingly

1: having or showing a lack of sympathy or tender feelings;

  * e.g., " ... she is a merciless competitor at board games of any kind "

•  Synonyms : 

•  affectless,

•  callous,

•  case-hardened,

•  cold-blooded,

•  compassionless,

•  desensitized,

•  hard,

•  hard-boiled,

•  hard-hearted,

•  heartless,

•  indurate,

•  inhuman,

•  inhumane,

•  insensate,

•  insensitive,

•  ironhearted,

•  obdurate,

•  pachydermatous,

•  pitiless,

•  remorseless,

•  ruthless,

•  slash-and-burn,

•  soulless,

•  stony,

•  stonyhearted,

•  take-no-prisoners,

•  thick-skinned,

•  uncharitable,

•  unfeeling,

•  unmerciful,

•  unsparing,

•  unsympathetic

•  Antonyms : 

•  charitable,

•  compassionate,

•  humane,

•  kindhearted,

•  kindly,

•  merciful,

•  sensitive,

•  softhearted,

•  sympathetic,

•  tender,

•  tenderhearted,

•  warm,

•  warmhearted