keep back vs throw away

keep back

verb
  • To hold back; to refuse to give or share. 

  • To restrict or restrain. 

  • To prevent (a pupil) from advancing in a course. 

  • To stay back; to refrain from approaching. 

throw away

verb
  • To give lightly, in an offhand manner. 

  • To intentionally throw an incomplete pass. 

  • To waste, to squander. 

  • To discard (trash, garbage, or the like), to toss out, to put in the trash, to dispose of. 

How often have the words keep back and throw away occurred in a corpus of books? (source: Google Ngram Viewer )