confederate vs take up with

confederate

verb
  • To combine in a confederacy. 

adj
  • of, relating to, or united in a confederacy 

  • banded together; allied. 

noun
  • A member of a confederacy. 

  • An accomplice in a plot. 

  • An actor who participates in a psychological experiment pretending to be a subject but in actuality working for the researcher. 

take up with

verb
  • To begin living together with; to lodge with. 

  • Used other than figuratively or idiomatically: see take, up, take up, with. 

  • To become interested in (something). 

  • To form a close relationship with (someone). 

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