personal grudge; personal enmity
Refers to a grudge or ill will rooted in personal, private matters, as opposed to official or public reasons.
His criticism stems from a personal grudge.
私怨で人を判断してはいけない。
You must not judge people out of personal enmity.
personal grudges and selfish desires
Compound of 私 (private, personal) and 怨 (grudge, resentment). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning of a personal grudge.