adverb (r)

• of a dreadful kind(adv.all)

  Example:
  There was a dreadfully bloody accident on the road this morning.
  

  Synonym:
  awfully, horribly
  

  source: wordnet30
• in a dreadful manner(adv.all)

  Synonym:
  dismally
  

  source: wordnet30
• In a dreadful manner; terribly.(adverb)

  source: webster1913