Level 5 · word 10,060 of 20,000

subterranean

/ˌsʌbtəˈreɪniən/ American
  • adj. 地下的, 秘密的
Definition
  • adj. existing or happening under the ground, or hidden and secret
Example
The old city has a subterranean tunnel system beneath its busy streets.
这座古城繁忙的街道下方有一套地下隧道系统。