Other forms: nauseatingly
Something nauseating makes you feel sick to your stomach. Your kitchen garbage can may be nauseating by the end of the week.
A bad smell or taste can be nauseating, but so can a terrible feeling or a horrible situation. The prospect of speaking in front of a crowd could be nauseating to you, or reading about a natural disaster. The adjective nauseating comes from nausea, which is a sick sensation or a feeling that you're about to vomit. The root of both words is the Latin nauseare, "to feel seasick, to vomit, or to feel disgust."