In Sweden, I was knocking back drink (4)
I believe the answer is:
wine
'drink' is the definition.
(wine is an alcoholic drink)
'in sweden i was knocking back' is the wordplay.
'in' indicates the answer is hidden within the clue.
'knocking back' says the letters should be written backwards.
'eniw' is hidden within 'sweden i was'.
'eniw' back-to-front is 'WINE'.
(Other definitions for wine that I've seen before include "Alcohol" , "Vino" , "Eg, Bordeaux" , "Something made with 16?" , "A sweet white cargo of Masefield's" .)