bright
1 beaming, blazing, brilliant, dazzling, effulgent, flashing, gleaming, glistening, glittering, glowing, illuminated, intense, lambent, luminous, lustrous, radiant, resplendent, scintillating, shimmering, shining, sparkling, twinkling, vivid
2 clear, clement, cloudless, fair, limpid, lucid, pellucid, pleasant, sunny, translucent, transparent, unclouded
3 acute, astute, aware, brainy, brilliant, clear-headed, clever, ingenious, intelligent, inventive, keen, quick, quick-witted, sharp, smart, wide-awake
4 auspicious, encouraging, excellent, favourable, golden, good, hopeful, optimistic, palmy, promising, propitious, prosperous, rosy
5 cheerful, chirpy (informal) full of beans (informal) gay, genial, glad, happy, jolly, joyful, joyous, light-hearted, lively, merry, sparky, upbeat (informal) vivacious
6 distinguished, famous, glorious, illustrious, magnificent, outstanding, remarkable, splendid
1 & 2 cloudy, dark, dim, dusky, gloomy, grey, overcast, poorly lit
3 dense, dim, dim-witted (informal) dull, dumb (informal) foolish, idiotic, ignorant, retarded, simple, slow, stupid, thick, unintelligent, witless