senator vs substitute

senator

noun
  • A member of the ancient Roman Senate. 

  • A member of the ruler’s council or governing council in general, a leading statesman. 

  • A member, normally elected, in the house or chamber of a legislature called a senate, as, for instance, the legislatures of the United States and Canada. 

  • A member of a governing council in other states in the ancient world. 

substitute

noun
  • One who enlists for military service in the place of a conscript. 

  • A player who is available to replace another if the need arises, and who may or may not actually do so. 

  • A replacement or stand-in for something that achieves a similar result or purpose. 

verb
  • To remove (a player) from the field of play and bring on another in his place. 

  • To serve as a replacement (for someone or something). 

  • To use in place of something else, with the same function. 

  • To use X in place of Y. 

  • To use Y in place of X; to replace X with Y. 

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