retirement vs retreat

retirement

noun
  • The state of being retired; seclusion. 

  • An act of retiring; withdrawal. 

  • The state of having permanently left one's employment, now especially at reaching pensionable age; the portion of one's life after retiring from one's career. 

  • The act of leaving one's career or employment permanently. 

retreat

noun
  • A period of retirement, seclusion, or solitude. 

  • 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 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. 

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 

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