flatten out vs put down

flatten out

verb
  • To win a fight, usually by punching someone until they are knocked over 

  • To make flat (something rough, folded or bumpy). 

  • To become more even. 

put down

verb
  • To execute (a person), especially extrajudicially. 

  • To drop someone off, or let them out of a vehicle. 

  • To euthanize (an animal). 

  • To make prices, or taxes, lower. 

  • To pay. 

  • To terminate a call; to hang up. 

  • To give something as a reason for something else. 

  • To add a name to a list. 

  • To insult, belittle, or demean. 

  • To halt, eliminate, stop, or squelch, often by force. 

  • To land. 

  • Used other than figuratively or idiomatically: see put, down. 

  • To write (something). 

  • To place a baby somewhere to sleep. 

  • To cease, temporarily or permanently, reading (a book). 

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