Этимология [ 'kwäm also 'kwom ] (noun.) circa 1530. Middle English cwalm, qualm "death, sickness, plague" from Old English cwealm (West Saxon) "death, disaster, plague," ūtcualm (Anglian) "utter destruction," related to cwelan "to die," cwellan "to kill". The other suggested etymology, less satisfying, is from Dutch kwalm "steam, vapor, mist," which also may be ultimately from the same Germanic root as quell. Sense softened to "feeling of faintness" 1530; meaning "uneasiness, doubt" is from 1553; that of "scruple of conscience" is 1649. An indirect connection between the Old English and modern senses is plausible, via the notion of "fit of sickness."