I fear tip improper for champagne, perhaps (8)
I believe the answer is:
aperitif
'champagne perhaps' is the definition.
(champagne might be an aperitif)
'i fear tip improper' is the wordplay.
'improper' is an anagram indicator.
'i'+'fear'+'tip'='ifeartip'
'ifeartip' is an anagram of 'APERITIF'.
'for' is the link.
(Other definitions for aperitif that I've seen before include "Alcoholic drink to whet the appetite" , "Stimulant taken before meal" , "Pre-meal appetiser" , "it leads to blow-out" , "Drink stimulating the appetite" .)