London reporter is outside, knocking back French liqueur (6)
I believe the answer is:
pernod
'french liqueur' is the definition.
(I've seen this in another clue)
'london reporter is outside knocking back' is the wordplay.
'is outside' indicates the answer is hidden within the clue (a word is around or outside the answer).
'knocking back' says the letters should be written backwards.
'donrep' can be found hidden inside 'london reporter'.
'donrep' back-to-front is 'PERNOD'.
(Other definitions for pernod that I've seen before include "Aperitif flavoured with aniseed" , "Brand of pastis" , "A liqueur flavoured with anise" , "Aniseed-flavoured liquor" , "Aniseed-flavoured aperitif" .)