adverb (r)

• completely and without qualification; used informally as intensifiers(adv.all)

  Example:
  A perfectly idiotic idea.
  You're perfectly right.
  

  Synonym:
  absolutely, dead, utterly
  

  source: wordnet30
• in a perfect or faultless way(adv.all)

  Example:
  She performed perfectly on the balance beam.
  Spoke English perfectly.
  Solved the problem perfectly.
  

  Antonym:
  amiss, imperfectly
  

  source: wordnet30
• In a perfect manner or degree; in or to perfection; completely; wholly; throughly; faultlessly.(adverb)

  source: webster1913