disinvolve vs sever

disinvolve

verb
  • To uncover; to unfold or unroll; to disentangle. 

sever

verb
  • To make a separation or distinction; to distinguish. 

  • To disconnect; to disunite; to terminate. 

  • To cut free. 

  • To suffer disjunction; to be parted or separated. 

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