An Etymological Dictionary of the German Language/Kummer
Kummer, m., ‘grief, sorrow, distress,’ from MidHG. kumber, m., ‘rubbish, refuse (thus still dial.), encumbering, oppression, distress, grief’; ModHG. mm, from MidHG. mb, as in Zimmer, Lamm, and Kamm. The word is wanting in all the OTeut. dials.; comp. ModDu. kommer, m., ‘grief, affliction; hare's dung’; MidE. combren, ‘to encumber, molest,’ E. to cumber. The cognates are very similar in sound to a Rom. class — Fr. décombres, ‘rubbish,’ Port. comoro, combro, ‘mound of earth, hillock,’ Ital. ingombro, ‘hindrance,’ Fr. encombrer, ‘to obstruct (with rubbish), block up’; MidLat. combrus, ‘mound of earth, barrier of felled trees, obstructing pile.’ The Teut. cognates seem to have passed into Rom.; for, besides the more recent form with r, we find in AS. and Scand. a variant with l, OIc. kumbl, ‘tumulus, barrow.’