underground

Definition

• n. a secret group organized to overthrow a government or occupation force
• adv. in or into hiding or secret operation
• adv. beneath the surface of the earth

Word forms

Plural

undergrounds

Example sentences

1. n.

   The underground is a fast way to travel around the city.

2. a.

   They held underground meetings to discuss their plans.

3. adv.

   The group operated underground to avoid detection.