Bitter drunk neat, tucked into by saint with halo, say (10)
I believe the answer is:
astringent
'bitter' is the definition.
(I've seen this before)
'drunk neat tucked into by saint with halo say' is the wordplay.
'drunk' indicates an anagram.
'tucked into by' means one lot of letters goes inside another.
'saint' becomes 's'.
'with' means one lot of letters goes inside another.
'halo say' becomes 'tring' (I can't explain this - if you can you should give a lot more credence to this answer).
'neat' is an anagram of 'aent'.
'aent' enclosing 's' is 'asent'.
'asent' enclosing 'tring' is 'ASTRINGENT'.
Can you help me to learn more?
(Other definitions for astringent that I've seen before include "Severe - checking the flow of blood" , "Sharp or severe in manner" , "Harsh" , "(Of taste) sharp, bitter" , "medical preparation" .)