沼

ぬま · numa · JLPT N1 · noun

swamp

🐸 沼 = water radical 氵 + 召 (sound part): standing water, like a swamp, bog or pond

The water radical 氵 on the left shows that 沼 is about water. Frogs often live in swamps and ponds, which links the frog emoji to the meaning.