An Etymological Dictionary of the German Language/geheuer
geheuer, adj., ‘secure against anything uncanny,’ from MidHG. gehiure, ‘gentle, graceful, free from anything uncanny’; comp. OHG. and OSax. unhiuri, ‘dreadful, terrible,’ AS. hŷre (heóre), ‘friendly, mild,’ OIc. hýrr, ‘mild.’ Indubitable cognates in the non-Teut. languages are wanting; perhaps Sans. çakrá, ‘strong’ (of deities) is allied, so that OHG. -hiuri would represent hegwro- (Aryan keqró-).