dirty
穢 centers on impurity and filth in a broad sense: something physically dirty, morally defiled, or spiritually unclean.
穢 combines 禾 (grain) with 歲, which likely contributes the sound and carries a sense of overgrowth or impurity. The exact historical development is uncertain, but the character is associated with dirtiness or defilement.
Grain 禾 beside the complex 歲 suggests crops overgrown with weeds or spoiled by age, making them dirty and impure.
For アイ, imagine an eye (アイ) that sees only dirt and impurity everywhere: the eye -> アイ, and the dirty grain 穢 is all it can focus on.
this impure world (as opposed to the pure land)
abhorrence of (living in) this impure world
night soil
person who gathers night soil
pure; clean; untouched; innocent
eta; group comprising the lowest rank of Japan's Edo-period caste system and whose work usually involved handling human bodies or animal carcasses
defiled body; unenlightened person's body
uncleanliness from contact with death, pregnancy, menstruation, etc.
ugly and filthy
various impurities (illness, menstruation, death, etc.)