Clandestine -

KlanˈDɛstɪn,ˈKlandɛstɪn

{adjective}

Kept secret or done secretively, especially because illicit.

"They deserved better than these clandestine meetings"

Synonyms: secret, covert, furtive, surreptitious, stealthy, cloak-and-dagger, hole-and-corner, hole-in-the-corner, closet, behind-the-scenes, backstairs, back-alley, under-the-table, hugger-mugger, concealed, hidden, private.


Underground -

ʌndəˈɡraʊnd

{Adjective}

1. Beneath the surface of the ground.

"The insects spend years underground as larvae"

Synonyms: Below ground, below the surface, under the earth, in the earth.

2. A group or movement organized secretly to work against an existing regime.

{Noun}

ˈʌndəɡraʊnd/

"The French underground"

Synonyms: Resistance movement, resistance, illegal opposition.


The Clandestine Underground