separate vs sunder

separate

verb
  • To divide (a thing) into separate parts. 

  • To disunite from a group or mass; to disconnect. 

  • To cause (things or people) to be separate. 

  • To divide itself into separate pieces or substances. 

adj
  • Apart from (the rest); not connected to or attached to (anything else). 

  • Not together (with); not united (to). 

noun
  • A printing of an article from a periodical as its own distinct publication and distributed independently, often with different page numbers. 

  • Anything that is sold by itself, especially articles of clothing such as blouses, skirts, jackets, and pants. 

sunder

verb
  • To part, separate. 

  • To break or separate or to break apart, especially with force. 

noun
  • a separation into parts; a division or severance 

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