embroil vs snarl up

embroil

verb
  • To implicate in confusion; to complicate; to jumble. 

  • To draw into a situation; to cause to be involved. 

snarl up

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

  • to become congested. 

  • To become tangled; to become entangled 

  • to entangle 

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

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