safely; without incident; successfully
Used when a journey, task, or event ends without trouble or harm. Often appears with verbs of returning, arriving, or completing.
彼は無事に家に帰った。
He returned home safely.
手術は無事に終わりました。
The operation was completed successfully.
peacefully; quietly; in peace
Describes a state or action free from disturbance or conflict. Less common than the 'safely' sense; often used in wishes or descriptions of a calm life.
どうか無事に過ごしてください。
Please spend your time in peace.
He arrived safely at the airport.
村は無事に暮らしていた。
The village lived quietly.
The surgery ended successfully.
The soldiers came back safely.
The family is living peacefully.
平穏 is a na-adjective/noun describing a calm, undisturbed state, while 無事に is the adverb used to say something happened or was done peacefully.
無事に (safely, without incident) shares the kanji 事 with 大事 (important, serious) and learners sometimes mix them up despite the very different meanings.
From 無事 (safety, peace) + adverbial particle に. 無事 is a Sino-Japanese compound of 無 (without) and 事 (matter, incident).