hinder vs keep back

hinder

verb
  • To delay or impede; to keep back, to prevent. 

  • To make difficult to accomplish; to act as an obstacle; to frustrate. 

adj
  • Of or belonging to that part or end which is in the rear or hind, or which follows. 

noun
  • The buttocks. 

keep back

verb
  • To stay back; to refrain from approaching. 

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

  • To restrict or restrain. 

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

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