noble undertaking; heroic deed
A somewhat formal or literary term for an action taken out of a sense of justice or moral duty, often implying courage or self-sacrifice.
His noble deed impressed many people.
That heroic undertaking will go down in history.
Compound of 義 (ぎ, 'righteousness, justice') and 挙 (きょ, 'action, undertaking'). The exact historical derivation is uncertain, but the word has been used in literary and formal contexts to describe morally courageous acts.