Wine merchant stocks up kind of liqueur (5)
I believe the answer is:
Here is my best explanation:
'kind of liqueur' is the definition.
(cream liqueur, liqueur de creme)
'wine merchant stocks up' is the wordplay.
'stocks' says the answer is hidden in the clue.
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'emerc' is hidden in the letters of 'wine merchant'.
'emerc' written backwards gives 'CREME'.