mull vs smoulder

mull

verb
  • To powder; to pulverize. 

  • To chop marijuana so that it becomes a smokable form. 

  • To dull or stupefy. 

  • To heat and spice something, such as wine. 

  • To work (over) mentally; to cogitate; to ruminate. 

  • To join two or more individual windows at mullions. 

noun
  • An inferior kind of madder prepared from the smaller roots or the peelings and refuse of the larger. 

  • A stew of meat, broth, milk, butter, vegetables, and seasonings, thickened with soda crackers. 

  • dirt; rubbish 

  • A thin, soft muslin. 

  • A promontory. 

  • A snuffbox made of the small end of a horn. 

  • The gauze used in bookbinding to adhere a text block to a book's cover. 

  • Marijuana that has been chopped to prepare it for smoking. 

smoulder

verb
  • To smother; to suffocate; to choke. 

noun
  • A disease of narcissus and related flowers caused by the fungus Botrytis narcissicola, and characterized by dark brown lesions on the leaves. 

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