Charge Germany following hostility (4)
I believe the answer is:
ward
'charge' is the definition.
(both can mean a child in one's care)
'germany following hostility' is the wordplay.
'germany' becomes 'd' (vehicle registration code for Deutschland).
'following' says to put letters next to each other.
'hostility' becomes 'war' (war is a kind of hostility).
'd' after 'war' is 'WARD'.
(Other definitions for ward that I've seen before include "Local administrative district" , "Hospital room with beds" , "Minor in the charge of a guardian" , "Hospital unit" , "zone for votes" .)