fetid

This term describes a smell that is not merely unpleasant but suggests active decomposition or stagnation. It evokes a visceral sense of organic decay, often associated with sulfur, rotting meat, or stagnant swamp water, creating a feeling of nausea or repulsion. While words like malodorous or smelly are general, this adjective specifically targets the scent of putrefaction. It is typically used in descriptive writing or scientific contexts to emphasize the oppressive and suffocating quality of a foul atmosphere.