underground

Từ điển WordNet v3.1 - WordNet Dictionary

I - noun

1. an electric railway operating below the surface of the ground (usually in a city)
- in Paris the subway system is called the 'metro' and in London it is called the 'tube' or the 'underground'
• Syn:
metro, tube, subway system, subway
• Hypernyms:
railway, railroad, railroad line, railway line, railway system
2. a secret group organized to overthrow a government or occupation force
• Syn:
resistance
• Hypernyms:
revolutionary group
• Hyponyms:
Maquis

II - adjective

1. under the level of the ground (Freq. 7)
- belowground storage areas
- underground caverns
• Syn:
belowground
• Similar to:
subsurface
2. conducted with or marked by hidden aims or methods
- clandestine intelligence operations
- cloak-and-dagger activities behind enemy lines
- hole-and-corner intrigue
- secret missions
- a secret agent
- secret sales of arms
- surreptitious mobilization of troops
- an undercover investigation
- underground resistance
• Syn:
clandestine, cloak-and-dagger, hole-and-corner, hugger-mugger, hush-hush,
secret, surreptitious, undercover
• Similar to:
covert

III - adverb

1. in or into hiding or secret operation
- the organization was driven underground
2. beneath the surface of the earth
- water flowing underground

• Từ đồng nghĩa / Synonyms:
  clandestine, cloak-and-dagger, hole-and-corner(a), hugger-mugger, hush-hush, secret, surreptitious, undercover, belowground, metro, tube, subway system, subway, resistance