Liberal is up before Liberal beak (4)
I believe the answer is:
bill
'beak' is the definition.
('bill' can be a synonym of 'beak')
'liberal is up before liberal' is the wordplay.
'liberal' becomes 'lib'.
'is up' says the letters should be written in reverse (in down clue: letters go upwards).
'before' is a charade indicator (letters next to each other).
'liberal' becomes 'l' (abbreviation).
'lib' backwards is 'bil'.
'bil'+'l'='BILL'
(Other definitions for bill that I've seen before include "Note - police - invoice - list" , "Projecting mouth of a bird" , "List of charges" , "Statute in draft before it becomes law" , "Police statement" .)