Capital: family has wasted it (8)
I believe the answer is:
kinshasa
'capital' is the definition.
(Kinshasa is an example)
'family has wasted it' is the wordplay.
'family' becomes 'kin' (synonyms).
'wasted' is an anagram indicator.
'it' becomes 'sa' (old-fashioned abbreviation for sex appeal).
'has' is an anagram of 'sha'.
'kin'+'sha'+'sa'='KINSHASA'
(Other definitions for kinshasa that I've seen before include "It was formerly Leopoldville" , "African capital on the Congo River" , "Capital of the Democratic Republic of the Congo" , "Congolese port" , "Capital of Zaire" .)