Fruit turning up every now and then in whisky (4)
I believe the answer is:
kiwi
'fruit' is the definition.
(I know that kiwi is a fruit)
'turning up every now and then in whisky' is the wordplay.
'turning up' shows that the letters should be reversed in order.
'every now and then' indicates alternate letters (letters selected at regular intervals).
'in'+'whisky'='inwhisky'
The alternate letters of 'inwhisky' are 'iwik'.
'iwik' back-to-front is 'KIWI'.
(Other definitions for kiwi that I've seen before include "Someone from Auckland?" , "Sacred Japanese peak" , "Symbol of New Zealand" , "New Zealand bird that does not fly" , "Chinese gooseberry" .)