The term "awful aroma" refers to a smell that is extremely unpleasant and offensive. There are several synonyms for this term that can be used to describe such a smell. One could describe it as a foul odor, reeking stench, putrid scent, fetid smell, or a noxious aroma. These synonyms convey a sense of disgust and repulsion, and are appropriate when describing unpleasant odors that can be noticed from a distance. It's advisable to use these synonyms instead of "awful aroma" to add variety and more context to the description of the smell.