darken vs shelter

darken

verb
  • To make foul; to sully; to tarnish. 

  • To become gloomy, darker in mood. 

  • To render gloomy, darker in mood. 

  • To cloud, obscure, or perplex; to render less clear or intelligible. 

  • To become dark or darker (having less light). 

  • To make dark or darker by reducing light. 

  • To make dark or darker in colour. 

  • To blind, impair the eyesight. 

  • To become dark or darker in colour. 

  • To be blinded, lose one’s eyesight. 

  • To get dark (referring to the sky, either in the evening or as a result of cloud). 

shelter

verb
  • To provide cover from damage or harassment; to shield; to protect. 

  • To take cover. 

noun
  • A refuge, haven or other cover or protection from something. 

  • An institution that provides temporary housing for homeless people, battered women, etc. 

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