Dim  —adj. (dimmer, dimmest) 1 a faintly luminous or visible; not bright. B indistinct. 2 not clearly perceived or remembered. 3 colloq. Stupid. 4 (of the eyes) not seeing clearly. —v. (-mm-) make or become dim.  take a dim view of colloq. Disapprove of.  dimly adv. Dimness n. [old english]