Dog among children seized (7)
I believe the answer is:
secured
'seized' is the definition.
(I've seen this before)
'dog among children' is the wordplay.
'dog' becomes 'cur' (both can mean a despicable person).
'among' indicates putting letters inside.
'children' becomes 'seed' (I've seen this in other clues).
'cur' inserted into 'seed' is 'SECURED'.
(Other definitions for secured that I've seen before include "Protected" , "Gained" , "Made safe or fastened safely" , "this way it's safe" , "Got by special effort" .)