dateless vs undying

dateless

adj
  • Timeless; immortal 

  • Without a date imprinted, assigned, or associated. 

  • Out of one's head; deranged. 

  • Thick-headed. 

  • Having no date—a meeting with a lover or potential lover. 

  • Without a start; immemorial 

undying

adj
  • permanent; never-ending; infinite 

How often have the words dateless and undying occurred in a corpus of books? (source: Google Ngram Viewer )