dim. adverb 1noun 1phrases 4 adverb1 •Abbreviation of diminuendo. noun1 •Abbreviation of diminutive. Phrases with dim. dim-wittedBeing a dimwit; stupid; foolish; simple. dim and distantOf a very long time ago, so as to be almost forgotten. dim outTo dim (lights) until they are totally off take a dim view ofTo dislike; to regard with skepticism, disbelief, disfavor, etc.