subterranean

/ˌˈsʌbtəˌreɪniən/

/səbtəˈreɪniɪn/

Other forms: subterraneanly

Subterranean is an adjective that describes something just below what can be seen, like the subterranean jealousy you hide under a smile and kind words for the actor who got the part you wanted.

Subterranean feelings and intentions are those you keep "on the down low." In fact, real things that are subterranean really are down low — underground, in fact. A subterranean worm lives under the earth's surface. A subterranean lair is a secret hideout dug under the dirt — or maybe it's just your basement. The word comes from the Latin subterraneus, from sub meaning "under" and terra meaning "earth."

Definitions of subterranean

1. adjective

   being or operating under the surface of the earth
   “subterranean passages”

   synonyms: subterraneous

   subsurface

   beneath the surface
2. adjective

   lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed)
   synonyms: subterraneous, ulterior

   covert

   secret or hidden; not openly practiced or engaged in or shown or avowed