unmitigable vs vain

unmitigable

adj
  • Not able to be mitigated or made less severe; not mitigable. 

vain

adj
  • Effecting no purpose; pointless, futile. 

  • Overly proud of oneself, especially concerning appearance; having a high opinion of one's own accomplishments with slight reason. 

  • Showy; ostentatious. 

  • Having no real substance, value, or importance; empty; void; worthless; unsatisfying. 

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