Anti-American intelligence (4)
I believe the answer is:
nous
'intelligence' is the definition.
(I've seen this before)
'anti-american' is the wordplay.
'anti' becomes 'no' (anti can mean opposing or without).
'american' becomes 'us' (abbreviation for United States).
'no'+'us'='NOUS'
(Other definitions for nous that I've seen before include "Sound practical judgement" , "Gumption" , "Common sense - intellect" , "Knowledge, experience" , "Our (French); practical intelligence (colloq.)" .)