A formal, literary yojijukugo referring to the distinction between right and wrong, or justice and injustice. Rare in everyday speech; more common in classical or formal writing.
It is important to distinguish right from wrong.
是非 is a common word for right and wrong, or pros and cons, used in everyday conversation. 正邪曲直 is a rare, formal yojijukugo with a similar meaning but much more literary and archaic.
A yojijukugo composed of 正 (correct), 邪 (wrong), 曲 (crooked), and 直 (straight). The exact historical derivation is uncertain, but it is a classical Chinese-derived compound.