heavy armor
Refers to thick, protective plating, often used in military, sci-fi, or gaming contexts for vehicles, mecha, or fortifications.
That tank is known for its heavy armor.
The heavily armored robot blocked the enemy's attack.
軽装甲 is the opposite, meaning 'light armor'.
Compound of 重 (heavy) and 装甲 (armor). The exact historical derivation is uncertain, but the word follows a common Sino-Japanese compounding pattern.