Source : Webster's Revised Unabridged Dictionary (1913)

Dim \Dim\, a. [Compar. {Dimmer}; superl. {Dimmest}.] [AS. dim;
   akin to OFries. dim, Icel. dimmr: cf. MHG. timmer, timber; of
   uncertain origin.]
   1. Not bright or distinct; wanting luminousness or clearness;
      obscure in luster or sound; dusky; darkish; obscure;
      indistinct; overcast; tarnished.

            The dim magnificence of poetry.       --Whewell.

            How is the gold become dim!           --Lam. iv. 1.

            I never saw The heavens so dim by day. --Shak.

            Three sleepless nights I passed in sounding on,
            Through words and things, a dim and perilous way.
                                                  --Wordsworth.

   2. Of obscure vision; not seeing clearly; hence, dull of
      apprehension; of weak perception; obtuse.

            Mine eye also is dim by reason of sorrow. --Job
                                                  xvii. 7.

            The understanding is dim.             --Rogers.

   Note: Obvious compounds: dim-eyed; dim-sighted, etc.

   Syn: Obscure; dusky; dark; mysterious; imperfect; dull;
        sullied; tarnished.

Source : WordNet®

dim
     adj 1: lacking in light; not bright or harsh; "a dim light beside
            the bed"; "subdued lights and soft music" [syn: {subdued}]
     2: lacking clarity or distinctness; "a dim figure in the
        distance"; "only a faint recollection"; "shadowy figures
        in the gloom"; "saw a vague outline of a building through
        the fog"; "a few wispy memories of childhood" [syn: {faint},
         {shadowy}, {vague}, {wispy}]
     3: made dim or less bright; "the dimmed houselights brought a
        hush of anticipation"; "dimmed headlights"; "we like
        dimmed lights when we have dinner" [syn: {dimmed}] [ant: {undimmed}]
     4: offering little or no hope; "the future looked black";
        "prospects were bleak"; "Life in the Aran Islands has
        always been bleak and difficult"- J.M.Synge; "took a dim
        view of things" [syn: {black}, {bleak}]
     5: slow to learn or understand; lacking intellectual acuity;
        "so dense he never understands anything I say to him";
        "never met anyone quite so dim"; "although dull at
        classical learning, at mathematics he was uncommonly
        quick"- Thackeray; "dumb officials make some really dumb
        decisions"; "he was either normally stupid or being
        deliberately obtuse"; "worked with the slow students"
        [syn: {dense}, {dull}, {dumb}, {obtuse}, {slow}]
     [also: {dimming}, {dimmed}, {dimmest}, {dimmer}]

dimmer
     n : a rheostat that varies the current through an electric light
         in order to control the level of illumination

dim
     v 1: switch (a car's headlights) from a higher to a lower beam
          [syn: {dip}]
     2: become or make darker; "The screen darkend"; "He darkened
        the colors by adding brown" [syn: {darken}] [ant: {brighten}]
     3: become dim or lusterless; "the lights dimmed and the curtain
        rose"
     4: make dim or lusterless; "Time had dimmed the silver"
     5: make dim by comparison or conceal [syn: {blind}]
     6: become vague or indistinct; "The distinction between the two
        theories blurred" [syn: {blur}, {slur}] [ant: {focus}]
     [also: {dimming}, {dimmed}, {dimmest}, {dimmer}]

dimmer
     See {dim}