Other forms: dimming, dimmed, dims
Dim light is weak light — enough to see by, not enough to read by. The lamp left on in the hallway at night, a pub with brown walls and one bulb over the bar, a phone screen turned right down.
Dim also covers anything faint or half-there: a dim memory of a holiday, a dim shape at the end of the corridor, a dim hope that the parcel will still arrive. It is a verb as well — you dim the lights before the film starts, and the lights dim by themselves as the curtain goes up. Calling a person dim is British and unkind, and it means slow to understand. The noun is dimness, and the phrase worth having is take a dim view of something, which means disapprove of it. Spelling: dim doubles its m before an ending, so dimmer, dimmest, dimming, dimmed.
1adjectivedimGiving or having only weak light.
“They ate by the dim light of a single candle.”
2adjectivevagueHard to see or to remember clearly.
“He had only a dim memory of the house by the sea.”
3adjectiveslowSlow to understand; not clever.
“Don't be dim — the answer is printed on the front page.”
4verbgrowTo make a light weaker, or to grow weaker.
“The lights dimmed and the audience went quiet.”
Also accepted in games: faint
Dim is old and homegrown. Old English dimm meant dark and gloomy, and also wretched, grievous and sad, so the light and the mood were one word from the start. It goes back through Proto-Germanic dimmaz, dark, to a root dʰem- that had to do with smoke and things being obscured. Icelandic still says dimmur for dark.
Proto-Indo-European
*dʰem- — to whisk, smoke; obscure
Proto-Germanic
*dimmaz — dark
Proto-West Germanic
*dimm
Old English
dim
Middle English
dim
English, today
dim
Built from
From Middle English dim, dym, from Old English dim, dimm (“dim, dark, gloomy; wretched, grievous, sad, unhappy”), from Proto-West Germanic dimm, from Proto-Germanic dimmaz (“dark”), from Proto-Indo-European dʰem- (“to whisk, smoke; obscure”). Compare Faroese dimmur (“dark”), Icelandic dimmur (“dark”) and dimma (“darkness”).
Etymology from Wiktionary, CC BY-SA