dateless vs perpetual

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 

perpetual

adj
  • Lasting forever, or for an indefinitely long time. 

  • Set up to be in effect or have tenure for an unlimited duration. 

  • Continuing; uninterrupted. 

  • Flowering throughout the growing season. 

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