dissipate vs lessen

dissipate

verb
  • To use up or waste; squander. 

  • To drive away, disperse. 

  • To vanish by dispersion. 

  • To cause energy to be lost through its conversion to heat. 

lessen

verb
  • To make less; to diminish; to reduce. 

  • To become less. 

conj
  • unless. 

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