incline vs retreat

incline

verb
  • To slope. 

  • To bend or move (something) out of a given plane or direction, often the horizontal or vertical. 

  • To tend to do or believe something, or move or be moved in a certain direction, away from a point of view, attitude, etc. 

noun
  • A portal of a subway tunnel. 

  • A slope. 

retreat

verb
  • To slope back. 

  • To withdraw military forces 

  • To shrink back due to generally warmer temperatures. 

  • To withdraw from a position, go back. 

  • a retreating forehead 

noun
  • A peaceful, quiet place affording privacy or security. 

  • The act of reversing direction and receding from a forward position. 

  • A bugle call or drumbeat signaling the lowering of the flag at sunset, as on a military base. 

  • A military ceremony to lower the flag. 

  • The move of a piece from a threatened position. 

  • A period of retirement, seclusion, or solitude. 

  • A period of meditation, prayer or study. 

  • The act of pulling back or withdrawing, as from something dangerous, or unpleasant. 

  • A signal for a military withdrawal. 

  • Withdrawal by military force from a dangerous position or from enemy attack. 

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