改善【かいぜん】
betterment, improvement, kaizen (Japanese business philosophy of continuous improvement)
善【ぜん】
good, goodness, right, virtue
親善【しんぜん】
friendship, goodwill, friendly relations, amity
善意【ぜんい】
virtuous mind, good intentions, good will, positive mindset, bona fides, good faith
慈善【じぜん】
charity, philanthropy
善良【ぜんりょう】
good (person, nature, etc.), good-natured, virtuous, honest
善悪【ぜんあく】
right and wrong, good and evil
勧善懲悪【かんぜんちょうあく】
rewarding good and punishing evil, poetic justice