1.
swamp, marsh
An area of low-lying, waterlogged land.
沼 refers to a swamp or marsh—wetland with standing water.
COMMON COMPOUNDS:
FIGURATIVE USAGE:
沼 and 泥沼 are used figuratively for situations difficult to escape:
SLANG:
In modern internet/otaku culture, 〜沼 or 沼にはまる means becoming deeply obsessed with a hobby, fandom, or interest—similar to "falling down a rabbit hole" or "getting hooked."