Currency of Vietnam (4)
I believe the answer is:
dong
'currency of vietnam' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for dong that I've seen before include "Ding's partner?" , "The --- with a Luminous Nose (Lear)" , "Deep ringing sound" , "Deep resonant clang - Vietnamese monetary unit" , "Lear's one had a luminous nose" .)