expugnable
/ɛksˈpʌɡnəbəl/Definitions
1. adjective
capable of being attacked or taken by force; open to assault
“The fort’s defenses made it expugnable to enemy forces, but the enemy still managed to breach them.”
2. noun
one that can be attacked or taken by force
“The general’s plan involved making the enemy’s position expugnable to his troops.”