Fetid means having a very foul or offensive odor, typically one that is strong and unpleasantly rotten or decayed. It is used to describe smells that are hard to tolerate, such as rotten food, stagnant water, or decaying organic matter. The term is often synonymous with stinky, foul, noisome, or malodorous, and it can be used in both literal and figurative senses.

• Literal use: A fetid swamp emits a nauseating stink due to decomposing plant and animal matter.
• Figurative use: The committee faced fetid rumors that polluted the atmosphere around the meeting.

If you’d like, I can provide example sentences or help with pronunciation and usage nuance in a specific variety of English.