沈没
ちんぼつ · chinbotsu · JLPT N1 · noun
sinking
🚢 Both characters have the water radical 氵: 沈 sink + 没 submerge = sinking
沈 and 没 each contain 氵 (water). 没 originally meant to plunge under water, so the compound describes something going under the surface, like a ship.
没 — water 氵 + 殳 (hand with weapon)
Originally depicted something sinking or being submerged in water, combining the water radical 氵 with 殳, suggesting a hand reaching into a whirlpool. The core sense was 'to sink, drown, disappear under water.' From there it extended to 'to vanish, not have,' giving the modern negative meaning 'not, have not.'