adverb (r)

• completely and without qualification; used informally as intensifiers(adv.all)

  Example:
  Utterly miserable.
  

  Synonym:
  absolutely, dead, perfectly
  

  source: wordnet30
• In an utter manner; to the full extent; fully; totally; as, utterly ruined; it is utterly vain.(adverb)

  source: webster1913