kosher vs taboo

kosher

verb
  • To kasher; to prepare (for example, meat) in conformity with the requirements of the Jewish law. 

adv
  • In a kosher manner; in accordance with kashrut. 

adj
  • Fit for use or consumption, in accordance with Jewish law (especially relating to food). 

  • In accordance with standards or usual practice. 

taboo

noun
  • An inhibition or ban that results from social custom or emotional aversion. 

  • Something which may not be used, approached or mentioned because it is sacred. 

adj
  • Culturally forbidden. 

  • Excluded or forbidden from use, approach or mention. 

verb
  • To ban. 

  • To avoid. 

  • To mark as taboo. 

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