非分 (fēi fèn) is an adjective meaning 'excessive' or 'unwarranted', describing desires, expectations, or actions that go beyond what is reasonable, appropriate, or rightfully one’s due. The character 非 means 'not' or 'un-', while 分 (fèn) here refers to one’s proper share, role, or rightful portion — literally, 'what belongs to one by virtue of position, status, or fairness'. Together, they convey the idea of overstepping natural or social boundaries.

This term carries a mild moral or normative judgment and is often used in formal or literary contexts — for instance, when criticizing unrealistic ambitions, inappropriate romantic interest, or greed. It frequently appears in phrases like 非分之想 (fēi fèn zhī xiǎng, 'an unwarranted thought/desire') or 非分要求 (fēi fèn yāoqiú, 'excessive demand'). While not harshly condemnatory, it implies social or ethical misalignment, making it common in advice, warnings, or reflective commentary.