Against having French apéritif endlessly for starters (9)
I believe the answer is:
antipasti
'for starters' is the definition.
(I've seen this before)
'against having french aperitif endlessly' is the wordplay.
'against' becomes 'anti' (prefix meaning against).
'having' means one lot of letters go next to another.
'french aperitif' becomes 'pastis' (I've seen this in another clue).
'endlessly' means to remove the last letter.
'pastis' with its last letter removed is 'pasti'.
'anti'+'pasti'='ANTIPASTI'
(Other definitions for antipasti that I've seen before include "Carpaccio and caponata" , "that's served in trattoria" , "hors d'oeuvre selection" , "Italian hors d'oeuvres" , "starters in Rome" .)