adverb (r)

• to a moderately sufficient extent or degree(adv.all)

  Example:
  The shoes are priced reasonably.
  

  Synonym:
  fairly, jolly, middling, moderately, passably, pretty, somewhat
  Antonym:
  immoderately, unreasonably
  

  source: wordnet30
• with good sense or in a reasonable or intelligent manner(adv.all)

  Example:
  Acted quite reasonably.
  

  Synonym:
  sanely, sensibly
  Antonym:
  unreasonably
  

  source: wordnet30
• In a reasonable manner.(adverb)

  source: webster1913