Taste or sample (3)
I believe the answer is:
sip
This clue is a double definition.
'taste' is the first definition.
(I've seen this in another clue)
'sample' is the second definition.
(I've seen this in another clue)
(Other definitions for sip that I've seen before include "Take a little of a drink" , "Tiny amount of drink" , "Thimbleful" , "Smallest drink" , "Small mouthful of fluid" .)