hear it again

1 : not letting light through : not transparent
2 : not reflecting light

Example sentence:
Our first step in transforming the room into a darkroom was to paint the windows black, which made them opaque.

Etymology:
"Opaque" comes from the Latin word "opacus," meaning "shaded, dark." Darkness is often associated with a lack of understanding, and that helped to give "opaque" the extended meaning "hard to understand." The opposite of "opaque" is "transparent." Something that is transparent transmits light or is sheer or fine enough to be seen through. "Transparent" also has an extended meaning; it can also refer to something "easily detected or understood; obvious."