Allege shortfall in uncontaminated wine (7)
I believe the answer is:
purport
'allege shortfall' is the definition.
'purport' can be an answer for 'allege' (I've seen this in another clue). I'm unsure of the 'shortfall' bit.
'uncontaminated wine' is the wordplay.
'uncontaminated' becomes 'pur' (I can't justify this - if you can you should give a lot more credence to this answer).
'wine' becomes 'port' (port is a kind of wine).
'pur'+'port'='PURPORT'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for purport that I've seen before include "Pretend; meaning" , "Meaning, substance" , "Seem or claim (to be)" , "Spirit" , "Intended meaning" .)