抜け穴

1. Origins, structure, and basic meaning

• Structure: 抜け穴 is read as ぬけあな and is a noun for a secret escape passage or, figuratively, a loophole in a rule or system.
• Basic usage: A passage under a wall appears in 秘密の抜け穴, while a weakness in rules appears in 制度の抜け穴.

2. Common pitfalls and similar expressions

• Passage and loophole
  • The physical sense of a hidden way out extends to a gap that can be exploited to evade a rule.
• Difference from 穴
  • 穴 is a hole in general, whereas 抜け穴 is specifically a way out or a figurative loophole around a restriction.