disengage vs unencumber

disengage

verb
  • To release or loosen from something that binds, entangles, holds, or interlocks. 

noun
  • A circular movement of the blade that avoids the opponent's parry 

unencumber

verb
  • To free something from incumbrance. 

  • To remove a burden, load or charge from something or someone. 

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