Vegetable rot (7)
I believe the answer is:
rhubarb
I believe this is a double definition.
'vegetable' is the first definition.
(I know that rhubarb is a type of vegetable)
'rot' is the second definition.
(both can mean rubbish or nonsense)
(Other definitions for rhubarb that I've seen before include "Plant stem used as fruit" , "Plant with thick stalks that are cooked in desserts" , "Reddish stalks - word repeated to simulate conversation" , "a word not meant to be understood" , "Red stalks" .)