Unit of parsley (5)
I believe the answer is:
sprig
'unit of parsley' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sprig that I've seen before include "Small branch or shoot" , "Purloined" , "Small stem with leaves or flowers" , "Tiny branch" , "A tack; a little shoot" .)