People very angry about new family (7)
I believe the answer is:
mankind
'people' is the definition.
'very angry about new family' is the wordplay.
'very angry' becomes 'mad' (I've seen this before).
'about' is an insertion indicator.
'new' becomes 'n'.
'family' becomes 'kin' ('kin' can be a synonym of 'family').
'n'+'kin'='nkin'
'mad' placed around 'nkin' is 'MANKIND'.
(Other definitions for mankind that I've seen before include "Human race" , "Everybody" , "People generally" , "all of us" , "Human beings collectively" .)