constrainment vs safekeeping

constrainment

noun
  • Synonym of constraint 

safekeeping

noun
  • the responsibility of a guardian 

  • the act of keeping something safe; protection from harm, damage, loss, or theft 

  • not returning checks; a system wherein banks keep checks (cheques) that people write, rather than returning them to the account holder with their monthly statement. 

  • the storage of assets in a protected area 

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