sink vs turn back

sink

verb
  • To push (something) into something. 

  • To demean or lower oneself; to do something below one's status, standards, or morals. 

  • To cause to decline; to depress or degrade. 

  • To drink (especially something alcoholic). 

  • To (directly or indirectly) cause a vessel to sink, generally by making it no longer watertight. 

  • To make by digging or delving. 

  • To pot; hit a ball into a pocket or hole. 

  • To pay absolutely. 

  • To be overwhelmed or depressed; to fail in strength. 

  • To descend or submerge (or to cause to do so) into a liquid or similar substance. 

  • To decrease in volume, as a river; to subside; to become diminished in volume or in apparent height. 

  • To experience apprehension, disappointment, dread, or momentary depression. 

noun
  • An object or callback that captures events; an event sink. 

  • A stage trapdoor for shifting scenery. 

  • Descending motion; descent. 

  • A depression in a stereotype plate. 

  • A destination vertex in a transportation network. 

  • An abode of degraded persons; a wretched place. 

  • A sinkhole. 

  • A drain for carrying off wastewater. 

  • An excavation smaller than a shaft. 

  • A habitat that cannot support a population on its own but receives the excess of individuals from some other source. 

  • One or several systems that remove currency from the game's economy, thus controlling or preventing inflation. 

  • A basin used for holding water for washing. 

  • A heat sink. 

  • A depression in land where water collects, with no visible outlet. 

  • The motion of a sinker pitch. 

  • A place that absorbs resources or energy. 

turn back

verb
  • To fold something back; to fold down. 

  • To cause to reverse direction and retrace one's steps. 

  • To return to a previous state of being. 

  • To reverse direction and retrace one's steps. 

  • To prevent or refuse to allow passage or progress. 

  • To adjust to a previous setting. 

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