combustive vs tumultuous

combustive

adj
  • Of, pertaining to, caused by, or partaking in combustion. 

tumultuous

adj
  • Causing or characterized by tumult; chaotic, disorderly, turbulent. 

  • Characterized by loud, confused noise. 

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