adverb (r)

• in an exhaustive manner(adv.all)

  Example:
  We searched the files thoroughly.
  

  Synonym:
  exhaustively
  

  source: wordnet30
• completely and absolutely (`good' is sometimes used informally for `thoroughly')(adv.all)

  Synonym:
  good, soundly
  

  source: wordnet30
• In a thorough manner; fully; entirely; completely.(adverb)

  source: webster1913