go under vs play dead

go under

verb
  • To collapse or fail, e.g. by going bankrupt. 

  • To enter a trance, state of hypnosis, etc. 

  • To be named; to call oneself. 

  • To descend into a body of water; to founder. 

play dead

verb
  • To lie very still, like a corpse. 

  • To act as though defeated while awaiting a chance to attack. 

How often have the words go under and play dead occurred in a corpus of books? (source: Google Ngram Viewer )