motivating vs tiring

motivating

adj
  • Effectively providing an incentive. 

tiring

adj
  • That tires or tire. 

noun
  • Bits of bone and tough organic material from a corpse given to hawks to abate their hunger. 

  • The action of tiring. 

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