An Etymological Dictionary of the German Language/Annotated/trübe
trübe, adjective, ‘turbid, gloomy, dull, dim,’ from Middle High German truëbe, adjective (truobe, adverb), Old High German truobi, adjective, ‘obscure, gloomy, dull’; allied to trüben, ‘to darken, tarnish, cast a gloom over,’ Middle High German truëben, Old High German truoben, ‘to darken, sadden.’ Compare Anglo-Saxon drôf, ‘dirty, troubled,’ Dutch droef, ‘dull, sad,’ Gothic drôbjan, ‘to confuse, lead astray, excite commotion,’ Anglo-Saxon drêfan, ‘to disturb, agitate, trouble.’ In the non-Teutonic languages there are no certain cognates of the Teutonic root dr(illegible text)b, ‘to confuse.’ —