WordNet

lacking in light; not bright or harsh; "a dim light beside the bed"; "subdued lights and soft music" (同)subdued
become dim or lusterless; "the lights dimmed and the curtain rose"
make dim or lusterless; "Time had dimmed the silver"
switch (a cars headlights) from a higher to a lower beam (同)dip
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" (同)faint, shadowy, vague, wispy

PrepTutorEJDIC

『薄暗い』,ほの暗い / はっきり見えない(聞こえない,理解できない) / (考え・記憶などが)はっきりしない,ぼんやりした / (色などが)くすんだ,光沢のない / 批判的な,悲観的な / 《話》(人が)ばかな,愚かな / (目が)かすんだ / …‘を'『薄暗くする』,ぼんやりさせる / 『薄暗くなる』,かすかになる