Former Greek currency unit (7)
I believe the answer is:
drachma
'former greek currency unit' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for drachma that I've seen before include "Former Greek currency unit" , "Old Greek settler" , "Old Greek currency" , "European currency replaced by the euro in 2002" , "Greek monetary unit which comprised 100 lepta" .)