replacement vs subalternate

replacement

noun
  • A person or thing that takes the place of another; a substitute. 

  • The removal of an edge of crystal, by one plane or more. 

  • The act of replacing something. 

subalternate

noun
  • A particular proposition, as opposed to a universal one. 

adj
  • Succeeding by turns; successive. 

  • Subaltern; inferior; subordinate. 

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