matchless vs optimal

matchless

adj
  • Without the use of matches for ignition. 

  • Having no mate. 

  • Having no match; without equal. 

optimal

adj
  • Describing a search algorithm that always returns the best result. 

  • The best, most favourable or desirable, especially under some restriction. 

noun
  • The best of its kind 

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