Cider cocktail with conservative reference book (9)
I believe the answer is:
directory
'reference book' is the definition.
(directory is a kind of reference book)
'cider cocktail with conservative' is the wordplay.
'cocktail' indicates anagramming the letters.
'with' means one lot of letters go next to another.
'conservative' becomes 'tory' (informal term for a Conservative Party member).
'cider' anagrammed gives 'direc'.
'direc'+'tory'='DIRECTORY'
(Other definitions for directory that I've seen before include "Telephone information service" , "See 5" , "list of contacts" , "Telephone book" , "Reference book" .)