Cheap wine, in British slang (5)
I believe the answer is:
plonk
'cheap wine in british slang' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for plonk that I've seen before include "Put down noisily" , "Ordinary wine" , "Wine - put down with a thud" , "Cheap red or white" , "Cheap wine (sl.)" .)