阴
yīn · HSK 2
overcast
☁️ 阴 = 阝(hill) + 月 (moon); the shady, moon-side of a hill
The left 阝 is a hill radical and 月 here marks the moon side. Hills block sunlight on one face, so 阴 came to mean shady, overcast, and the Yin (dark/negative) principle paired with 阳 (yang, sunny side).
阴 — left 阝(mound) + 月 (moon)
Originally written 陰, combining the 'mound/hill' radical 阝 with 侌 (clouds covering the sun), suggesting the shaded north side of a hill. The simplified form 阴 replaces the phonetic with 月 (moon), reinforcing the idea of darkness, shadow, and the feminine yin principle opposed to 阳 (yang).