Animosity injured family (3,5)
I believe the answer is:
bad blood
'animosity' is the definition.
(synonyms)
'injured family' is the wordplay.
'injured' becomes 'bad' (I've seen this in other clues).
'family' becomes 'blood' (I've seen this in another clue).
'bad'+'blood'='BAD BLOOD'
(Other definitions for bad blood that I've seen before include "Ill-feeling (between people)" , "Hostile feelings" , "Ill feeling of tainted sanguinary sort" , "Ill feeling, animosity of sanguinary sort" , "Feeling of animosity or hostility" .)