Show off volume by family member (5)
I believe the answer is:
vaunt
'show off' is the definition.
(thesaurus)
'volume by family member' is the wordplay.
'volume' becomes 'v'.
'by' says to put letters next to each other.
'family member' becomes 'aunt' (I've seen this before).
'v'+'aunt'='VAUNT'
(Other definitions for vaunt that I've seen before include "Show off" , "crow" , "Talk boastfully of" , "Boast about (something), often excessively" , "brag" .)