menial vs workhorse

menial

noun
  • A servant, especially a domestic servant. 

  • A person who has a subservient nature. 

adj
  • Of or relating to unskilled work. 

  • Servile; low; mean. 

  • Of or relating to work normally performed by a servant. 

workhorse

noun
  • Anyone or anything that does a lot of work; something or someone who works consistently or regularly. 

  • A horse used primarily for manual labor; a draft horse. 

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