act up vs mistake

act up

verb
  • To misbehave; to cause trouble. 

  • To perform the duties of an appointment senior to that actually held; to deputise for a superior. 

mistake

verb
  • To understand wrongly, taking one thing or person for another. 

noun
  • An error; a blunder. 

  • A pitch which was intended to be pitched in a hard-to-hit location, but instead ends up in an easy-to-hit place. 

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