opaque
1. opaque \o--'pa-k\ aj [L opacus] 1: neither reflecting nor emitting light 2a: not transparent or translucent 2b: impervious to forms of radiant energy other than visible light 3a: hard to understand or explain : UNINTELLIGIBLE 3b: OBTUSE, STUPID - opaque.ly av 2. opaque n : something that is opaque; specif : an opaque paint for blocking out portions of a photographic negative or print