An Etymological Dictionary of the German Language/Qual
Qual, f., ‘torment, pain,’ from MidHG. quâl, quâle (kále), OHG. and OSax. quâla, f., ‘anguish, torture’; comp. Du. kwaal, ‘pain,’ AS. cwalu, ‘violent death.’ To this word is allied a str. root vb. OHG. quëlan (MidHG. quëln), ‘to be in violent pain’ (AS. cwëlan, ‘to die’), of which the factitive is ModHG. quälen, MidHG. quęln, OHG. quęllen (from *qualljan), ‘to torture, torment to death.’ The Teut. root qel (qal) is primit. connected with Lith. gelti, ‘to prick’ (gélia, ‘it pains’), gėlà, ‘pain,’ OSlov. žalĭ, ‘hurt’ (Aryan root gē̆l).