"Smelling high heaven" is an idiom that means something smells extremely bad. However, there are numerous synonyms that can be used to describe a foul odor. Some of the synonyms for "smelling high heaven" include reeking, stinky, putrid, foul, rancid, fetid, malodorous, and noxious. Each of these words paints an unpleasant picture to describe a smell that is overwhelming and repugnant. It's important to have a rich vocabulary to accurately convey the intensity of a smell, and these synonyms give us a spectrum of foul smells to choose from in our descriptions.