Rough cider, as in cocktail (7)
I believe the answer is:
sidecar
'cocktail' is the definition.
(I know that Sidecar is a type of cocktail)
'rough cider as' is the wordplay.
'rough' indicates an anagram (a rough or broken ordering of the letters).
'cider'+'as'='cideras'
'cideras' with letters rearranged gives 'SIDECAR'.
'in' is the link.
(Other definitions for sidecar that I've seen before include "Is raced (anag.)" , "that biker may take with him" , "Vehicle" , "that's suitable for a non-driver" , "passenger compartment" .)