not bright or clear 不鲜 明的; 不清楚的: a dull colour, glow, thud 暗淡的颜色﹑ 昏暗的光﹑ 沉闷的响声 * dull (ie cloudy) weather 阴沉的天气 * dull of hearing, ie slightly deaf 听力不佳. 
slow in understanding; stupid 迟钝的; 呆笨的: a dull pupil, class, mind 迟钝的学生﹑ 一班学生﹑ 头脑. 
lacking interest or excitement; boring; monotonous 枯燥无味的; 令人厌烦的; 单调的: The conference was deadly dull. 会议开得死气沉沉的. 
not sharp 不锋利的; 钝的: a dull knife 钝刀. 
(of pain) not felt sharply （指疼痛）感觉不明显的, 隐约感觉到的: a dull ache 隐约的疼痛. 
(of trade) not busy; slow （指生意）萧条的, 清淡的: There's always a dull period after the January sales. 在一月份大减价之後市面总要有一段清淡时期. 
(idm 习语) (as) ,dull as `ditch-water (infml 口) very boring 极沉闷乏味的.> dull v [I, Tn] (cause sth to) become dull （使某事物）变钝, 变迟钝: Watching television dulls one's wits. 看电视能使人头脑迟钝. * She took drugs to dull the pain. 她吃了药以减轻疼痛. * (fig 比喻) Time had dulled the edge of his grief. 岁月流逝冲淡了他的忧伤.
dullness n [U].
dully adj.