An element in the Entish phrase Taurelilómëa-tumbalemorna Tumbaletaurëa Lómëanor (LotR/467), which in one place Tolkien described as meaning “very dark, full of darkness”, a combination of the prefix li(n)- “many” and lómëa “shadowed, gloomy”. A more literal interpretation would be “having many nights”; compare lilótëa “having many flowers” (VT42/18). As such, I think it is safe to say this word is a poetic Entish elaboration, not likely to be used in ordinary Quenya speech.
Quenya
lilómëa
very dark, full of darkness
lilómëa
adjective. very dark, full of darkness
lilómëa adj. "very dark, full of darkness" (PE17:81)