rotted

Anything that's rotted has decayed and broken down. You have to be careful when you're walking through an old, abandoned house with rotted floors.

If you discover some old potatoes in the back of your refrigerator, they may be absolutely fine. Or you may want to cut out the rotted parts and use the rest. And when you walk in the woods, you'll see a lot of rotted things if you look, like rotted tree stumps and last year's layer of rotted leaves. Rotted, from the verb rot, is rooted in the Old English rotian, "to decay or putrefy."