1. A sudden feeling of sickness, faintness, or nausea.
2. A sudden disturbing feeling: qualms of homesickness.
3. An uneasy feeling about the propriety or rightness of a course of action.
Larry had no qualms about stealing from the cafeteria cash register. He didn't even feel guilty when someone else was blamed.
After hiding Lori's bike as an April Fool's joke, I began to have qualms. What if she thought it was stolen and called the police?