" keenly "

1: as in eagerly, excitedly;

•  Synonyms : 

•  avidly,

•  eagerly,

•  excitedly,

•  impatiently,

•  enthusiastically,

•  exuberantly,

•  madly,

•  rhapsodically,

•  sky-high,

•  fanatically,

•  rabidly,

•  warmly,

•  zealously

•  Antonyms : 

•  apathetically,

•  indifferently,

•  lukewarmly,

•  perfunctorily,

•  aloofly,

•  disinterestedly,

•  impassively,

•  incuriously,

•  hesitantly,

•  reluctantly,

•  unwillingly

2: as in sharply, acutely;

•  Synonyms : 

•  acutely,

•  harshly,

•  piercingly,

•  poignantly,

•  severely,

•  sharply,

•  blackly,

•  darkly,

•  dismally,

•  distressfully,

•  distressingly,

•  dourly,

•  drearily,

•  forlornly,

•  gloomily,

•  glumly,

•  joylessly,

•  mirthlessly,

•  miserably,

•  morosely,

•  pessimistically,

•  somberly,

•  sullenly,

•  cruelly,

•  hurtfully,

•  ill,

•  rancorously,

•  abjectly,

•  cheerlessly,

•  crestfallenly,

•  dejectedly,

•  despairingly,

•  despondently,

•  disconsolately,

•  dispiritedly,

•  downheartedly,

•  low-spiritedly,

•  agonizingly,

•  bitterly,

•  dolefully,

•  dolorously,

•  grievously,

•  hard,

•  hardly,

•  inconsolably,

•  lugubriously,

•  mournfully,

•  painfully,

•  plaintively,

•  regretfully,

•  resentfully,

•  ruefully,

•  sadly,

•  sorely,

•  sorrowfully,

•  unhappily,

•  wailfully,

•  woefully,

•  wretchedly

•  Antonyms : 

•  blissfully,

•  gladly,

•  happily,

•  joyfully,

•  joyously,

•  cheerfully,

•  cheerily,

•  delightedly,

•  gaily,

•  gleefully,

•  good-naturedly,

•  lightheartedly,

•  merrily,

•  mirthfully,

•  rejoicingly,

•  sunnily,

•  blithely,

•  blithesomely,

•  calmly,

•  casually,

•  dispassionately,

•  easily,

•  impassively,

•  indifferently,

•  lightly,

•  nonchalantly,

•  stoically,

•  unconcernedly,

•  favorably,

•  well

1: able to sense slight impressions or differences;

  * e.g., " ... pilots with especially keen eyesight "

•  Synonyms : 

•  acute,

•  delicate,

•  fine,

•  perceptive,

•  quick,

•  sensitive,

•  sharp

•  Antonyms : 

•  blunt,

•  blunted,

•  dull,

•  dulled,

•  obtuse

2: causing intense discomfort to one's skin;

  * e.g., " ... the keen wind gave me chapped lips "

•  Synonyms : 

•  biting,

•  bitter,

•  cutting,

•  penetrating,

•  piercing,

•  raw,

•  sharp,

•  shrewd,

•  smarting,

•  stinging

•  Antonyms : 

•  airheaded,

•  birdbrained,

•  boneheaded,

•  brain-dead,

•  brainless,

•  bubbleheaded,

•  chuckleheaded,

•  dense,

•  dim,

•  dim-witted,

•  doltish,

•  dopey,

•  dorky,

•  dull,

•  dumb,

•  dunderheaded,

•  empty-headed,

•  fatuous,

•  gormless,

•  half-witted,

•  knuckleheaded,

•  lamebrain,

•  lunkheaded,

•  mindless,

•  obtuse,

•  opaque,

•  pinheaded,

•  senseless,

•  simple,

•  slow,

•  slow-witted,

•  soft,

•  softheaded,

•  stupid,

•  thick,

•  thickheaded,

•  thick-witted,

•  unbrilliant,

•  unintelligent,

•  unsmart,

•  vacuous,

•  weak-minded,

•  witless

3: having an edge thin enough to cut or pierce something;

  * e.g., " ... lanced the boil with a keen scalpel "

•  Synonyms : 

•  cutting,

•  edged,

•  edgy,

•  ground,

•  honed,

•  sharp,

•  sharpened,

•  stropped,

•  trenchant,

•  whetted

•  Antonyms : 

•  atrocious,

•  awful,

•  execrable,

•  lousy,

•  pathetic,

•  poor,

•  rotten,

•  terrible,

•  vile,

•  wretched