Trouble after fourth of brandies -- one might get hammered (4)
I believe the answer is:
nail
'one might get hammered' is the definition.
(I've seen this in another clue)
'trouble after fourth of brandies' is the wordplay.
'trouble' becomes 'ail' (synonyms).
'after' is a charade indicator (letters next to each other).
'fourth of brandies' becomes 'n' (4th letter of 'brandies').
'ail' put after 'n' is 'NAIL'.
(Other definitions for nail that I've seen before include "Fastening device" , "Hit this on the head to be bang-on" , "Fixer (on finger?)" , "Fixing device" , "Hammered individual" .)