bulwark
noun /ˈbʊlwək/
  /ˈbʊlwɜːrk/
- [usually singular] bulwark (against something) (formal) a person or thing that protects or defends something
- a bulwark against extremism
 - At the time fascism had many supporters in the West, who saw it as a bulwark against communism.
 
 - [countable] a wall built as a defence                                     
 - [usually plural] the part of a ship’s side that is above the level of the deck
 
Word Originlate Middle English: from Middle Low German and Middle Dutch bolwerk; related to bole and work.