bulwark vs security

bulwark

noun
  • A defense or safeguard. 

  • A defensive wall or rampart. 

  • A breakwater. 

  • Any means of defence or security. 

  • The planking or plating along the sides of a nautical vessel above her gunwale that reduces the likelihood of seas washing over the gunwales and people being washed overboard. 

verb
  • To fortify something with a wall or rampart. 

  • To provide protection of defense for something. 

security

noun
  • Something that secures. 

  • Proof of ownership of stocks, bonds or other investment instruments. 

  • Property etc. temporarily relinquished to guarantee repayment of a loan. 

  • Something that secures the fulfillment of an obligation or law. 

  • A guarantee. 

  • The condition of not being threatened, especially physically, psychologically, emotionally, or financially. 

  • An organization or department responsible for providing security by enforcing laws, rules, and regulations as well as maintaining order. 

  • Freedom from apprehension. 

  • A tradeable financial asset, such as a share of stock.ᵂ 

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