Dictionary and Thesaurus

Definition of Underground

• (n.) The place or space beneath the surface of the ground; subterranean space.
• (a.) Being below the surface of the ground; as, an underground story or apartment.
• (a.) Done or occurring out of sight; secret.
• (adv.) Beneath the surface of the earth.

Synonyms of Underground

• Resistance
• Metro
• Tube
• Subway System
• Subway
• Belowground
• Clandestine
• Cloak-And-Dagger
• Hole-And-Corner
• Hugger-Mugger
• Hush-Hush
• Secret
• Surreptitious
• Undercover

Antonyms of Underground

Homophones of Underground