Antonyms of adj luminous

1 sense of luminous

Sense 1
aglow (predicate), lambent, lucent, luminous -- (softly bright or radiant; "a house aglow with lights"; "glowing embers"; "lambent tongues of flame"; "the lucent moon"; "a sky luminous with stars")

INDIRECT (VIA bright) -> dull -- (emitting or reflecting very little light; "a dull glow"; "dull silver badly in need of a polish"; "a dull sky")

Similarity of adj luminous

1 sense of luminous

Sense 1
aglow (predicate), lambent, lucent, luminous -- (softly bright or radiant; "a house aglow with lights"; "glowing embers"; "lambent tongues of flame"; "the lucent moon"; "a sky luminous with stars")
       => bright (vs. dull) -- (emitting or reflecting light readily or in large amounts; "the sun was bright and hot"; "a bright sunlit room")