lasting vs undependable

lasting

adj
  • Persisting for an extended period of time. 

noun
  • A durable woollen material formerly used for women's shoes. 

  • The act or process of shaping footwear on a last. 

undependable

adj
  • Not dependable. 

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