Limits assistant's aperitif? I very much doubt it (4)
I believe the answer is:
asif
'limits assistant's aperitif?' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'i very much doubt it' is the wordplay.
'i' becomes 'a'.
'very' becomes 'so' (both can mean 'extremely').
'much' means to remove the last letter (much but not all of the word).
'doubt it' becomes 'if' (I can't explain this - if you can you should give a lot more credence to this answer).
'so' with its last letter removed is 's'.
'a'+'s'+'if'='ASIF'
Can you help me to learn more?
(Other definitions for asif that I've seen before include "yeah, right!" , "Common name in Pakistan" , "I very much doubt it!" .)