semblance vs similitude

semblance

noun
  • likeness, similarity; the quality of being similar. 

  • the way something looks; appearance; form 

similitude

noun
  • Similarity or resemblance to something else. 

  • A way in which two people or things share similitude. 

  • Someone or something that closely resembles another; a duplicate or twin. 

  • A parable or allegory. 

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