Good-natured, socialist family (7)
I believe the answer is:
kindred
'family' is the definition.
(kindred means one's relatives)
'good-natured socialist' is the wordplay.
'good-natured' becomes 'kind' (associated in meaning).
'socialist' becomes 'red' (red can informally mean a socialist).
'kind'+'red'='KINDRED'
(Other definitions for kindred that I've seen before include "These spirits have similar tastes" , "Closely related" , "Similarity in character" , "Relatives" , "Associated - relations" .)