Qualm: 1. Sickness, disease, pestilence, or death. As in "A thousand slain and not of qualm ystorve [not dead of sickness]" (Chaucer in The Canterbury Tales) 2. A sudden sick feeling. As in "A qualm came over me, a horrid nausea and the most deadly shuddering." (Robert Louis Stevenson in "Dr. Jekyll and Mr. Hyde") 3. Today, a sudden attack of emotion or principle, particularly in not following one's conscience or better judgment.