<adj.all> subterranean passages a subsurface flow of water
lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed)
<adj.all> subterranean motives for murder looked too closely for an ulterior purpose in all knowledge
Subterranean \Sub`ter*ra"ne*an\, Subterraneous \Sub`ter*ra"ne*ous\, a. [L. subterraneus; sub under + terra earth. See {Terrace}.] Being or lying under the surface of the earth; situated within the earth, or under ground; as, subterranean springs; a subterraneous passage. -- {Sub`ter*ra"ne*ous*ly}, adv.