off-color vs ribald

off-color

adj
  • Dirty, vulgar or obscene, especially in a way that is unpleasant. 

  • Feeling mildly unwell. 

  • Different than usual. 

  • Of the wrong color. 

ribald

adj
  • Coarsely, vulgarly, or lewdly amusing; referring to sexual matters in a rude or irreverent way. 

noun
  • An individual who is filthy or vulgar in nature. 

How often have the words off-color and ribald occurred in a corpus of books? (source: Google Ngram Viewer )