sub terrestrial (adjective) subterrestrial: underground
Sinonime: alternative,
avant-garde,
clandestine,
concealed,
covert, experimental,
hidden, hush-hush, hypogeal, hypogean, hypogeous, on the QT, on the sly,
private,
radical,
resistant, resistive,
revolutionary, subterranean,
surreptitious, unbowed,
unconventional, under wraps, undercover,
unusual