the words bright and dim are antonyms because they are opposites
Bright.
Bright
Dim.
dense, dim-witted, dull, foolish, moronic, simple minded
dark, gloomy, murky, shady, shadowy, dusky, tenebrous, cloudy, grey, dismal, overcast
Bright.
The word opposite to the word dim is bright.
If you're talking about a gender difference, then the opposite is a bright girl. Otherwise the opposite of 'bright boy' is 'dull boy'
An antonym for dim is low light
Dim
bright
it has bright
bright
dim, hazy, cloudy
Dim.
Dim stars are far more common than bright ones. But because they are dim, we can't see them without good telescopes.
Bright