dateless vs permanent

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 

permanent

adj
  • Without end, eternal. 

  • Lasting for an indefinitely long time. 

noun
  • A card whose effects persist beyond the turn on which it is played. 

  • A chemical hair treatment imparting or removing curliness, whose effects typically last for a period of weeks; a perm. 

  • Given an n⨯n matrix a_ij,, the sum over all permutations 𝜋, of ∏ᵢ₌₁ⁿa_i𝜋(i). 

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