right and wrong; merits and demerits; propriety
A yojijukugo used to discuss the moral or practical rightness and wrongness of a matter, often in contexts of judgment or evaluation.
Behavior that distinguishes right from wrong is expected.
Let's calmly judge the rights and wrongs of this issue.
善悪 is a more common, general term for 'good and evil' or 'right and wrong', while 是非善悪 is a formal yojijukugo that adds the nuance of 'pros and cons' or 'merits' (是非) to the moral judgment.
是非 alone often means 'right and wrong' or 'pros and cons' in a practical sense, but 是非善悪 combines it with 善悪 to emphasize both practical and moral dimensions.
A yojijukugo composed of 是非 (right and wrong, pros and cons) and 善悪 (good and evil, right and wrong). The combination reinforces the idea of evaluating both practical merits and moral correctness.