Drink served up after prohibition — one of those with strings attached (5)
I believe the answer is:
banjo
'one of those with strings attached' is the definition.
(banjo is a string instrument)
'drink served up after prohibition' is the wordplay.
'drink' becomes 'OJ' (orange juice).
'served up' shows that the letters should be reversed in order (in a down clue, going upwards).
'after' is a charade indicator (letters next to each other).
'prohibition' becomes 'ban' (ban is a kind of prohibition).
'oj' reversed gives 'jo'.
'jo' put after 'ban' is 'BANJO'.
(Other definitions for banjo that I've seen before include "Softly (music)" , "Uke's relative" , "Relative of the guitar" , "Guitar-like instrument" , "something that's played on" .)