Illegal trader at home, discussing alcoholic drink (7)
I believe the answer is:
insider
'illegal trader' is the definition.
(I've seen this in another clue)
'home discussing alcoholic drink' is the wordplay.
'home' becomes 'in' (to be in is to be (at) home).
'discussing' shows a homophone (sound like).
'alcoholic drink' becomes 'cider' (cider is an alcoholic beverage).
'cider' sounds like 'sider'.
'in'+'sider'='INSIDER'
'at' acts as a link.
(Other definitions for insider that I've seen before include "One with special knowledge" , "member of favoured group?" , "Particularly advantaged person" , "One dealing illegally" , "Dire sin (anag)" .)