Put an end to whisky (6)
I believe the answer is:
scotch
I believe this is a double definition.
'put an end' is the first definition.
(I've seen this before)
'whisky' is the second definition.
(Scotch is an example)
'to' acts as a link.
(Other definitions for scotch that I've seen before include "Kind of whisky spelt without an e" , "__ broth; soup variety" , "tot" , "Put an end to, say rumour" , "Thwart - sort of broth, mist or egg" .)