1. Being or operating under the surface of the earth
   - subterranean 
2. Lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed)
   - subterranean, ulterior

See also: covert, subsurface

• communications technology
• communications theory
• communicative
• communicativeness
• communicator
• communicatory
• communion
• communion table
• communiqué
• communisation
• communise
• communism
• Communism Peak
• communist
• Communist China
• communist economy
• Communist Manifesto
• Communist Party
• Communist Party of Kampuchea
• communistic
• community
• community center
• community centre
• community chest
• community college