What is the meaning of Qualm?

A feeling of apprehension, doubt, fear etc.

A sudden sickly feeling; queasiness.

A prick of the conscience; a moral scruple, a pang of guilt.

Mortality; plague; pestilence.

A calamity or disaster.

To have a sickly feeling.

Plague, disease or sickness; that which afflicts.

The effects, fruits, or ravages of plague.

Killing (as a concept or as an instance)

Source: wiktionary.org