enlighten vs snarl up

enlighten

verb
  • To make something clear to (someone); to give knowledge or understanding to. 

  • To supply with light. 

snarl up

verb
  • to become congested. 

  • To become tangled; to become entangled 

  • to entangle 

  • To block (traffic); to cause (traffic) to be congested. 

  • To put into disarray; contort; confuse; muddle up 

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