Murmuring 'Money holds nothing before golf!' (6)
I believe the answer is:
cooing
'murmuring' is the definition.
(cooing is a kind of murmuring)
'money holds nothing before golf' is the wordplay.
'money' becomes 'coin' (I've seen this before**).
'holds' indicates putting letters inside.
'nothing' becomes 'o' (looks like zero - 0).
'before' says to put letters next to each other.
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'coin' placed around 'o' is 'cooin'.
'cooin'+'g'='COOING'
(Other definitions for cooing that I've seen before include "Sounding like a dove" , "Murmuring like a pigeon" , "Making pigeon-like noises" , "that'll go after billing?" .)