Sour-tasting stuff and nonsense (7)
I believe the answer is:
rhubarb
'nonsense' is the definition.
(rhubarb can mean nonsense or rubbish)
'sour-tasting stuff' is the wordplay.
'sour-tasting' becomes 'rhu' (I am not sure about this - if you are sure you should believe this answer much more).
'stuff' becomes 'barb' (barb is a kind of stuff).
'rhu'+'barb'='RHUBARB'
'and' acts as a link.
Can you help me to learn more?
(Other definitions for rhubarb that I've seen before include "making contribution to murmuring" , "Reddish leafstalks cooked and eaten as fruit" , "Word of theatrical mumbling" , "mutterings in the theatre" , "Plant with poisonous leaves and edible stems" .)