Fellow accommodating illicit tavern is party guy? (12)
I believe the answer is:
conservative
'party guy?' is the definition.
(member of the Conservative Party)
'fellow accommodating illicit tavern is' is the wordplay.
'fellow' becomes 'cove' (British slang term).
'accommodating' indicates putting letters inside.
'illicit' indicates an anagram (I've seen this in other clues).
'tavern'+'is'='tavernis'
'tavernis' with letters rearranged gives 'nservati'.
'cove' placed around 'nservati' is 'CONSERVATIVE'.
(Other definitions for conservative that I've seen before include "Traditional; cautious" , "right-wing?" , "politician" , "Averse to change" , "(Of dress) conventional and sober" .)