Rotting, spoiled food is an example of something that might be described as fetid.
I caught the fetid odor of dirty socks.
Origin of fetid
- Middle English from Latin fētidus from fētēre to stink
From American Heritage Dictionary of the English Language, 5th Edition
- From the Latin adjective, fetidus (“having offensive odour”) (often incorrectly foetidus, giving rise to the variant spelling), originally feteo (“to stink”).