armour

A protective attitude or emotional barrier against vulnerability or hurt.

"She put up an emotional armour."

Protective metal plating on military vehicles, ships, or aircraft.

"The tank's thick armour withstood the blast."

To equip or cover something with a protective layer or plating.

"They armoured the vehicle against attacks."

Protective covering, typically metal, worn by warriors in battle.

"Knights wore heavy armour into battle."