agitate vs chirl

agitate

verb
  • To disturb or excite; to perturb or stir up (a person). 

  • To cause to move with a violent, irregular action; to shake. 

chirl

verb
  • To emit a low sound; to warble. 

noun
  • A kind of musical warble. 

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