noun (n)

• skillful performance or ability without difficulty

  terampil prestasi atau kemampuan tanpa kepayahan

  Example:
  His quick adeptness was a product of good design.
  

  Synonym:
  adroitness, deftness, facility, quickness
  

  source: wordnet30
• The quality of being adept; skill.

  kualitas yang mahir; keterampilan.

  source: webster1913