expression, godan verb (-mu)
feel satisfied; feel at ease; have peace of mind
Used when a feeling of unease, guilt, or dissatisfaction is resolved, often after taking some action. Common in negative forms like 気が済まない (can't feel satisfied/at ease).
謝ってしまえば気が済むだろう。
You'll feel better once you apologize.
彼は文句を言
He can't feel satisfied unless he complains.