satisfactory vs tower of strength

satisfactory

noun
  • Somebody or something that meets requirements without exceeding them. 

  • The rating given to somebody or something that meets requirements without exceeding them. 

adj
  • Causing satisfaction; agreeable or pleasant; satisfying. 

  • Done to satisfaction; adequate or sufficient. 

  • Making atonement for a sin; expiatory. 

tower of strength

noun
  • A person who supplies strong and reliable support, especially in difficult times. 

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