Sangar is a word commonly used in the military to refer to a protective bunker or shelter. There are several synonyms that can be used interchangeably with the word 'sangar,' including fortification, stronghold, bastion, redoubt, and citadel. These synonyms convey a similar meaning of a secure and defensive structure that provides protection against enemy attacks. Other related terms that can be used include shelter, bunker, and trench, which all describe structures designed to protect individuals from harm during a battle or conflict. Regardless of the specific synonym used, the underlying concept is the same - a fortified structure or shelter designed to protect individuals from danger and harm.