ganja vs skunkweed

ganja

noun
  • marijuana, as used for smoking. 

skunkweed

noun
  • strong-smelling cannabis 

  • Any of several American plants that have an offensive odour, but especially Croton texensis and Polemonium viscosum 

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