1. A justification, explanation, or cause that cannot be logically supported, morally justified, or reasonably defended
His decision to fire employees without warning was based on an indefensible reason.
Sua decisão de demitir funcionários sem aviso prévio foi baseada em uma razão indefensável.
2. An argument or rationale that is fundamentally flawed or unsustainable upon scrutiny
The company offered only an indefensible reason for the sudden price increase.
A empresa ofereceu apenas uma razão indefensável para o aumento repentino de preço.