Adj. defending &c v.; defensive; mural^; armed, armed at all points, armed cap-a-pie, armed to the teeth; panoplied^; iron-plated, ironclad; loopholed, castellated, machicolated^, casemated^; defended &c v.; proof against. armored, ballproof^, bulletproof; hardened.

Now this one has the added advantage of being bulletproof.

Now this one has the added advantage of being bulletproof.

They can reach the burrowing human beings in shelters which are bulletproof; they are the omnipresent threat of death.