not bright; obscure from lack of light or emitted light

a dim room; a dim flashlight.

not seen clearly or in detail; indistinct

a dim object in the distance.

not clear to the mind; vague

a dim idea.

not brilliant; dull in luster

a dim color.

not clear or distinct to the senses; faint

a dim sound.

not seeing clearly

eyes dim with tears.

tending to be unfavorable; not likely to happen, succeed, be favorable, etc.

a dim chance of winning.

not understanding clearly.

rather stupid; dim-witted.

to make dim or dimmer.

to switch (the headlights of a vehicle) from the high to the low beam.

to become or grow dim or dimmer. ?

dim out, (in wartime) to reduce the night illumination of (a city, ship, etc.) to make it less visible from the air or sea, as a protection from enemy aircraft or ships. ?

take a dim view of, to regard with disapproval, skepticism

or dismay

Her mother takes a dim view of her choice of friends.

adjective

bright , brilliant , clear , distinct , light , favorable , good , intelligent , smart , intense , vivid

verb

brighten , lighten

adjective

blah , bleary , blurred , caliginous , cloudy , dark , dingy , dreary , dull , dusk , dusky , faded , faint , flat , fuzzy , gloomy , gray , ill-defined , indistinct , lackluster , lightless , mat , monotone , monotonous , murky , muted , obscured , opaque , overcast , pale , poorly lit , shadowy , sullied , tarnished , tenebrous , unclear , unilluminated , vague , weak , depressing , disapproving , discouraging , skeptical , somber , suspicious , unpromising , boorish , dense , dim-witted , doltish , dumb , oafish , obtuse , slow , slow on uptake , stupid , thick * , weak-minded , obscure , drab , muddy , lusterless , blurry , hazy , misty , blear , foggy , indefinite , undistinct , crepuscular , fuliginous , wan

verb

becloud , bedim , befog , blear , blur , cloud , dull , eclipse , fade , fog , haze , lower , muddy , obfuscate , pale , tarnish , turn down , gloom , mist , overcast , overshadow , shadow , hebetate , stupefy , bleak , blurred , cloudy , darken , darkish , dense , depressing , disapproving , dreary , dusky , efface , faint , foggy , gloomy , hazy , lackluster , mysterious , negative , obnubilate , obscure , obtuse , shadowy , soft , somber , subdued , unclear , unfavorable , unlit , vague