noun (n)

• the quality of being at hand when needed(noun.attribute)

  Synonym:
  availability, availableness, handiness
  Antonym:
  inaccessibility, unavailability
  

  source: wordnet30
• the attribute of being easy to meet or deal with(noun.attribute)

  Synonym:
  approachability
  Antonym:
  unapproachability
  

  source: wordnet30
• The quality of being accessible, or of admitting approach; receptibility.(noun)

  source: webster1913