1. impossible to justify or excuse; not able to be defended with good reasons
2. impossible to protect from attack; not able to be defended militarily
Usage: military

Examples

• His behavior toward the employees was completely indefensible.
• The company’s decision to cut safety measures is indefensible.
• She found his excuses for being late indefensible.
• The castle’s position on the plain made it indefensible against attack.
• The general declared the outpost indefensible and ordered a retreat.
• Their treatment of the prisoners was morally indefensible.
• The politician’s comments were widely criticized as indefensible.