If you suspect that something in your yard is in a state of putrefaction, there's probably something stinky and rotten out there.
The relatives of this word in English all resemble it and fit neatly into one meaning category, "rotten." The mother of them all is putrid, from Latin putris, "rotten." This leads to putrefy, which means "make rotten," and finally putrefaction, the process of rotting or a state of being rotten. The ending is -faction rather than -fication on the pattern of many nouns that have Latin facere in their pasts: benefaction, malefaction, and liquefaction — to name a few.