A synonym for heavily armored is armor-clad.
Other synonyms for heavily armored are shielded, protected, ironclad, bony plated, bulletproof, steel plated and armor plated.
Other related words to armor or heavily armored include.
Security, protection, plate, mail, hard shell, guard, defense, bulletproof vest and body armor.
An example of heavily armored would be a military vehicle or a ship that is covered with a tough metal layer as a defense against an attack.
Or certain animals having a protective layer or shell.
The meaning of armored is having a protective covering, such as armor or bone.
Comprising units making use of armored vehicles.
Or an armored brigade. (of glass) toughened.