Out of control American given sanction (4)
I believe the answer is:
amok
'out of control' is the definition.
(I've seen this before)
'american given sanction' is the wordplay.
'american' becomes 'Am' (abbreviation in some contexts).
'given' is a charade indicator (letters next to each other).
'sanction' becomes 'ok' (to OK something is to approve or sanction it).
'am'+'ok'='AMOK'
(Other definitions for amok that I've seen before include "Frenziedly" , "Berserk" , "going wild" , "(Run) wild, out of control" , "crazy" .)