endlessly vs for keeps

endlessly

adv
  • In an endless manner; continuously without limit. 

for keeps

prep
  • With an agreement or intention to retain what one gains or receives. 

  • Permanently, so that one can keep something indefinitely. 

  • With a strong competitive resolve to win or succeed, as in sports or business. 

How often have the words endlessly and for keeps occurred in a corpus of books? (source: Google Ngram Viewer )