noun (n)

• the quality of being able to meet a need satisfactorily:(noun.attribute)

  Example:
  He questioned the adequacy of the usual sentimental interpretation of the Golden Rule.
  

  Synonym:
  adequateness
  Antonym:
  inadequacy, inadequateness
  

  source: wordnet30
• the quality of being sufficient for the end in view(noun.attribute)

  Synonym:
  sufficiency
  Antonym:
  deficiency, inadequacy, insufficiency
  

  source: wordnet30
• The state or quality of being adequate, proportionate, or sufficient; a sufficiency for a particular purpose; as, the adequacy of supply to the expenditure.(noun)

  source: webster1913