" efficiently "

1: as in expertly, deftly;

•  Synonyms : 

•  ably,

•  adeptly,

•  adroitly,

•  competently,

•  deftly,

•  dexterously,

•  expertly,

•  masterfully,

•  proficiently,

•  skillfully,

•  easily,

•  easy,

•  effortlessly,

•  facilely,

•  fluently,

•  freely,

•  handily,

•  hands down,

•  lightly,

•  painlessly,

•  readily,

•  smoothly,

•  well,

•  instinctively,

•  intuitively,

•  naturally,

•  spontaneously

•  Antonyms : 

•  arduously,

•  hardly,

•  laboriously,

•  strenuously,

•  awkwardly,

•  clumsily,

•  gracelessly,

•  ham-handedly,

•  ineptly,

•  maladroitly,

•  unskillfully,

•  meticulously,

•  painfully,

•  painstakingly,

•  thoroughly,

•  assiduously,

•  diligently,

•  indefatigably,

•  industriously,

•  intensely,

•  intently,

•  mightily,

•  sedulously,

•  tirelessly

1: producing or capable of producing a desired result;

  * e.g., " ... that manual lawn mower is not a very efficient tool for doing a huge yard "

•  Synonyms : 

•  effective,

•  effectual,

•  efficacious,

•  fruitful,

•  operative,

•  potent,

•  productive

•  Antonyms : 

•  fruitless,

•  ineffective,

•  ineffectual,

•  inefficient,

•  inoperative,

•  unfruitful,

•  unproductive,

•  useless