What term is used to express a feeling of sickness or uneasiness?

The term that accurately conveys a feeling of sickness or uneasiness is "nausea." Nausea specifically refers to the sensation that often precedes vomiting and is frequently described as an uncomfortable feeling arising from the stomach or digestive system. This term is commonly associated with various causes, such as motion sickness, pregnancy, or illness, and provides a clear and focused description of the physiological and emotional experience.

"Qualm" does represent a feeling of uneasiness or apprehension, typically in a moral context rather than the physical sensation of sickness. Although it can imply discomfort or hesitation, it does not specifically refer to the physical sensation of nausea. The other terms, "dizziness" and "discomfort," also describe different sensations: dizziness relates to a spinning or unstable feeling, while discomfort could pertain to a range of unpleasant sensations but does not specifically indicate the medical or physiological connotation that nausea carries.