Putrescent (7)
'putrescent' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for rotting that I've seen before include "corruption?" , "Decaying" , "Sultanate in NW Borneo" , "Going bad" , "Putrid" .)
(Other definitions for decayed that I've seen before include "Atrophied" , "Rotted, decomposed" , "Rotten" .)