Prohibition includes weapon for publican (6)
I believe the answer is:
barman
'for publican' is the definition.
(thesaurus)
'prohibition includes weapon' is the wordplay.
'prohibition' becomes 'ban' (ban is a kind of prohibition).
'includes' indicates putting letters inside.
'weapon' becomes 'arm' (synonyms).
'ban' placed around 'arm' is 'BARMAN'.
(Other definitions for barman that I've seen before include "Bloke at counter" , "Who could help with getting mops and brooms" , "Drinks server" , "In pub he might pull" , "Worker in pub" .)