1. under the level of the ground
- underground caverns
2. conducted with or marked by hidden aims or methods
- underground resistance
Sentences with underground as an adjective:
- There is an underground tunnel that takes you across the river.
- These criminals operate through an underground network.
1. in or into hiding or secret operation
- the organization was driven underground
2. beneath the surface of the earth
- water flowing underground
Sentences with underground as an adverb:
- The tunnel goes underground at this point.
1. a secret group organized to overthrow a government or occupation force
Similar word(s): resistance
Definition categories: group
2. 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'
1. To route electricity distribution cables underground