undefeatably

Such that it cannot be defeated.

Japanese Meaning

無敵である様子、敗北し得ない状態 / 必勝である、絶対に勝利が保証される

The hero fought undefeatably, inspiring his comrades to hold the line.

英雄は打ち負かされないように戦い、仲間たちに陣地を守る勇気を与えた。

Sense（1）

Such that it cannot be defeated.

more undefeatably

（ comparative ）

most undefeatably

（ superlative ）