lackey vs plodder

lackey

noun
  • A fawning, servile follower. 

  • A footman, a liveried male servant. 

verb
  • To attend, wait upon, serve obsequiously. 

plodder

noun
  • One who plods. 

  • A person who works slowly, making a great effort with little result; a person who studies laboriously. 

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