adverb (r)

• for a limitless time(adv.all)

  Example:
  No one can live forever.
  

  Synonym:
  eternally, everlastingly, evermore
  

  source: wordnet30
• for a very long or seemingly endless time(adv.all)

  Example:
  She took forever to write the paper.
  We had to wait forever and a day.
  

  Synonym:
  forever and a day
  

  source: wordnet30
• without interruption(adv.all)

  Synonym:
  always, constantly, incessantly, perpetually, uninterruptedly
  

  source: wordnet30
• Through eternity; through endless ages; eternally.(adverb)

  source: webster1913