Wine expert? Lightweight! (8)
I believe the answer is:
portable
'lightweight' is the definition.
(thesaurus)
'wine expert?' is the wordplay.
'wine' becomes 'port' (port is a kind of wine).
'expert?' becomes 'able' (I've seen this in other clues).
'port'+'able'='PORTABLE'
(Other definitions for portable that I've seen before include "Handy - lightweight" , "desirable type of pension" , "Designed to be easily carried" , "Easily transported" , "Able to be carried" .)