Englishopaque
adjective
1 the bottle was made of opaque glass so that the contents could not be seen:
nontransparent, cloudy, filmy, blurred, smeared, hazy, misty, dirty, dingy, muddy, muddied, grimy, smeary.
▷antonyms transparent, translucent, clear.
2 federalism renders the decision-making process opaque and bureaucratic:
obscure, unclear, dense, uncertain, indeterminate, mysterious, puzzling, perplexing, baffling, mystifying, confusing, enigmatic, inexplicable, unexplained, concealed, hidden, unfathomable, incomprehensible, impenetrable, vague, ambiguous, Delphic, indefinite, indistinct, hazy, foggy, nebulous, equivocal, doubtful, dubious, oblique, elliptical, oracular, cryptic, deep, abstruse, recondite, arcane, esoteric, recherché;
informal as clear as mud.
▷antonyms limpid, clear.