1.
muddy swamp, bog
A literal swamp or marsh filled with deep mud.
2.
quagmire, morass, hopeless situation
A situation that is difficult to escape from and keeps getting worse, like being stuck in mud.
Usage
Sense 2 is the more common one: a situation that gets worse the more you struggle, like sinking deeper into mud. 泥沼化する describes a dispute or war turning into one.
Common collocations
Related Words
Compare:
沼地 (swamp)