Family Golf giving dull sound (5)
I believe the answer is:
clang
'dull sound' is the definition.
(dull metallic sound)
'family golf' is the wordplay.
'family' becomes 'clan' (I've seen this before).
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'clan'+'g'='CLANG'
'giving' acts as a link.
(Other definitions for clang that I've seen before include "Resounding metallic noise" , "A loud ringing sound" , "Dull sound of a bell" , "Noise from crane" , "Ring loud and deep" .)