grub vs tar baby

grub

noun
  • A dirty person. 

  • An insect at an immature stage of its life cycle. 

  • Food. 

  • A despicable person; a lowlife. 

verb
  • To scavenge or in some way scrounge, typically for food. 

  • To dig; to dig up by the roots; to root out by digging; often followed by up. 

tar baby

noun
  • A black person. 

  • A difficult, abstract problem that worsens as one attempts to handle it; a "sticky" situation, especially one where attempts to make it better only make it worse. 

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