A tot (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
dram
'a tot' is the definition.
(both can mean an alcoholic drink)
This is the entire clue.
(Other definitions for dram that I've seen before include "Small drink of whisky" , "little weight" , "Small drink of scotch" , "Wee drop of whisky?" , "shot" .)