底なし沼

1. Origins, structure, and basic meaning

• Structure: 底なし沼 (そこなしぬま) is a compound noun for a swamp with no apparent bottom and, figuratively, an inescapable situation.
• Basic usage: 森の底なし沼に足を取られる depicts being physically trapped in a swamp, while 生活は底なし沼のようだ compares debt-ridden life to an inescapable mire.

2. Common pitfalls and similar expressions

• Literal place and ようだ simile
  • 底なし沼に identifies a literal place in the forest, whereas 底なし沼のようだ is a comparison formed with ようだ. No actual water or swamp is asserted in the second life situation.