Copper and quiet old man getting together for a drink (5)
I believe the answer is:
cuppa
'a drink' is the definition.
(cuppa is a kind of drink)
'copper and quiet old man getting together' is the wordplay.
'copper' becomes 'cu' (chemical symbol).
'and' is a charade indicator (letters next to each other).
'quiet' becomes 'p' (music symbol for 'piano').
'old man' becomes 'pa' (both can mean father).
'getting together' is a charade indicator (letters next to each other).
'cu'+'p'+'pa'='CUPPA'
'for' is the link.
(Other definitions for cuppa that I've seen before include "Refreshing brew" , "Drink of tea (informal)" , "Drink of tea (colloq.)" .)