noun
past misdeeds; old crimes
Refers to wrongdoings or crimes committed in the past, often with a nuance of them being brought to light or remembered later. Somewhat formal or literary.
彼の旧悪が新聞で暴かれた。
His past misdeeds were exposed in the newspaper.
旧悪を理由に解雇された。
He was fired because of his old crimes.
Compound of 旧 (old, former) and 悪 (evil, wrongdoing). The exact historical derivation is uncertain, but the meaning is transparent from its components.