A marsh, swamp or bog — a wet area with stagnant water, often with dense vegetation.
雨の後、あの谷は小さな沼のようになった。
After the rain, that valley became like a small marsh.
探検隊は深い沼地を慎重に渡った。
The expedition carefully crossed the deep marshland.
この沼には珍しい渡り鳥がよく来る。
Rare migratory birds often come to this swamp.
(slang) An obsession or addiction; being so absorbed in something that it’s hard to get out (e.g., “gacha swamp,” “idol swamp”). Used online as a metaphorical suffix or noun.
そのソシャゲは本当に沼で、つい課金が止まらない。
That mobile game is a real money sink — I can’t stop spending.
彼は歴史漫画の沼にハマって、古書を集め始めた。
He fell into the history-manga rabbit hole and started collecting old books.
「沼」が付く言い方は、その趣味に深くのめり込んでいることを表すネットスラングだ。
The expression with “沼” is internet slang indicating someone is deeply into a hobby.
(internet slang) A derogatory term referring to an unattractive man. It’s offensive and should be avoided.
ネットでは時に容姿の悪い男性を『沼』と呼ぶことがあるが、差別的なので避けるべき表現だ。
On the internet, unattractive men are sometimes called “沼,” but it’s discriminatory and should be avoided.
(internet slang, derogatory) A slur used to insult people with intellectual disabilities (e.g., in compounds like 池沼). Highly offensive; do not use.
『沼』を障害者への蔑称として使うのは差別的であり、決して許されない。
Using “沼” as a slur against disabled people is discriminatory and completely unacceptable.