Measure of spirits (4)
I believe the answer is:
dram
'measure of spirits' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dram that I've seen before include "Pick-me-up" , "little weight" , "Apothecary's weight, 60 grains" , "slug" , "Nip, snifter" .)