degrade, disparage, belittle, demote
貶 centers on lowering someone's worth or status: degrading, disparaging, belittling, or demoting.
貶 combines 貝 (shell, money) with 乏 (lacking), suggesting a reduction in value or status. The exact historical development is uncertain, but the component combination fits the meaning of degrading or demoting.
A shell (貝) that is lacking (乏) value: imagine a once-prized shell being tossed aside as worthless, degraded and belittled.
For ヘン, picture a hen pecking at a lowly shell, degrading it further: hen -> ヘン, and the hen's disdain mirrors the kanji's meaning.