汚

A phono-semantic compound:

水 (water) — semantic component

亐 (originally a place-name / grammatical particle) — phonetic component

The character originally referred to water that is no longer clean, such as muddy, stagnant, or contaminated water. From this concrete meaning, the sense broadened metaphorically to include:

- moral corruption

- disgrace

- damage to purity, reputation, or dignity

Thus, 汚 bridges physical impurity and ethical pollution.

오염 (汚染) — pollution; contamination

오수 (汚水) — sewage; dirty water

오물 (汚物) — filth; refuse

명예를 더럽히다 (汚名) — to stain one’s reputation

오욕 (汚辱) — humiliation; disgrace

Related characters:

濁 — turbid (muddy liquid)

垢 — dirt (grime)

穢 — defilement (ritual impurity)

潔 — clean (semantic opposite)

汚 often contrasts with 潔 (“clean; pure”), especially in moral or philosophical texts.

In classical literature, 汚 frequently appears in discussions of:

- virtue vs. corruption

- moral decay of officials

- pollution of customs or governance

The metaphorical sense (“to stain honor”) is often stronger than the physical sense.

汙 — historical/graphic variant