disassociate vs sunder

disassociate

verb
  • To separate (oneself); to dissolve one's association with a person, group, or situation. 

  • To separate into smaller discrete units, as with analysis. 

  • To separate; to disunite; to disintegrate; to dissolve. 

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 disassociate and sunder occurred in a corpus of books? (source: Google Ngram Viewer )