A word in the Qenya Lexicon appearing as ᴱQ. huiva “murky”, an adjectival form of ᴱQ. hui “dark, murk, fog” (QL/41). It appeared in a variant form fuiva in the name ᴱQ. Ungwe Fuiva “the Spider of Night” (QL/80; PME/104).
Neo-Quenya: Given that the root √PHUY and the related word Q. huinë “gloom, deep shadow” continues to appear in Tolkien’s later writings, I think ᴺQ. huiva could still be used in Neo-Quenya. However, since huinë was used for a deep darkness such as a night without stars or moon (VT41/8), I think huiva should be limited to describing lightless or nearly lightless conditions. Obscured or very weak light (dim, gloomy) would be Q. úcalima or lómëa.
huiva adj. "murky" (LT1:253)