Coin ace used to get drug (7)
I believe the answer is:
cocaine
'drug' is the definition.
(I know that cocaine is a type of hard drug)
'coin ace used' is the wordplay.
'used' indicates anagramming the letters.
'coin'+'ace'='coinace'
'coinace' with letters rearranged gives 'COCAINE'.
'to get' is the link.
(Other definitions for cocaine that I've seen before include "Addictive drug of oceanic origin" , "Drug from ace coin" , "Drug, crack" , "14 (anag)" , "Charlie" .)