Describing something that does not allow light to pass through, and is therefore impossible to see through.
It can also figuratively describe something unclear, obscure, or difficult to understand, such as information or language.
An opaque object or substance is not transparent or translucent, it blocks light.
It prevents vision, either literally or metaphorically, hindering comprehension. .
DARK DULL
FILMY MUDDY MURKY SHADY
CLOUDY
UNCLEAR OBSCURE CLOUDED
NOTCLEAR
CLEARASMUD
UNFATHOMABLE IMPENETRABLE
UNINTELLIGIBLE