An Etymological Dictionary of the German Language/kühn
kühn, adj., ‘bold, daring,’ from MidHG. küen, küene, OHG. chuoni, ‘bold, eager for combat, strong’; comp. the non-mutated variant in the MidHG. and OHG. derivative kuonheit, ‘boldness,’ and in the OHG. adv. chuono. It corresponds to MidLG. koene, Du. koen, AS. cêne, ‘bold,’ E. keen (the adj. is obsolete in Suab. and Bav.); Scand. kœ́nn, ‘wise, experienced.’ The latter must at one time have been the prevalent sense in West Teut. also, as is proved by the ModHG. proper name Konrad; OHG. and MidHG. Kuonrât (without mutation, like OHG. and MidHG. kuonheit), AS. Cênrêd (Goth. *Kônirêþs), may have meant ‘giving wise advice.’ Teut. kôn-i- (lit. ‘one that can understand, sensible’) is orig. a verbal adj. from the vb. kennen, können, hence the West Teut. sense ‘bold,’ compared with the OIc. meaning, must be regarded as derivative. All intellectual and moral conceptions of the OTeut. period are related more or less to war and conflict (comp. bald, schnell, and Krieg).