dateless vs undated

dateless

adj
  • 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. 

  • Timeless; immortal 

  • Without a start; immemorial 

undated

adj
  • Not marked with a date. 

  • Of a style that will not go out of fashion; a classic. 

  • Rising and falling in waves toward the margin, as a leaf; waved. 

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