An Etymological Dictionary of the German Language/trübe
trübe, adj., ‘turbid, gloomy, dull, dim,’ from MidHG. truëbe, adj. (truobe, adv.), OHG. truobi, adj., ‘obscure, gloomy, dull’; allied to trüben, ‘to darken, tarnish, cast a gloom over,’ MidHG. truëben, OHG. truoben, ‘to darken, sadden.’ Comp. AS. drôf, ‘dirty, troubled,’ Du. droef, ‘dull, sad,’ Goth. drôbjan, ‘to confuse, lead astray, excite commotion,’ AS. drêfan, ‘to disturb, agitate, trouble.’ In the non-Teut. languages there are no certain cognates of the Teut. root dr(illegible text)b, ‘to confuse.’ —