cop out vs prevaricate

cop out

verb
  • To avoid or shirk, either by failing to perform, or by performing in a grossly insufficient, negligent, or superficial manner. 

  • To plead guilty and ask for mercy. 

prevaricate

verb
  • To shift or turn from direct speech or behaviour; to deviate from the truth; to evade the truth; to waffle or be (intentionally) ambiguous. 

  • To undertake something falsely and deceitfully, with the purpose of defeating or destroying it. 

  • To collude, as where an informer colludes with the defendant, and makes a sham prosecution. 

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