a wall of earth or other material built for defense; rampart.

any protection against external danger, injury, or annoyance

The new dam was a bulwark against future floods.

any person or thing giving strong support or encouragement in time of need, danger, or doubt

Religion was his bulwark.

Usually, bulwarks. Nautical . a solid wall enclosing the perimeter of a weather or main deck for the protection of persons or objects on deck.

to fortify or protect with a bulwark; secure by or as if by a fortification.

noun

weak point

noun

barrier , bastion , buffet , buttress , citadel , defense , embankment , fort , fortress , guard , mainstay , outwork , parapet , partition , protection , rampart , redoubt , safeguard , security , stronghold , vallation , breakwater , buffer , defend , fence , fortification , palladium , protect , secure , shield , support , wall