American representative not characteristic (8)
I believe the answer is:
atypical
'not characteristic' is the definition.
(I've seen this before)
'american representative' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'representative' becomes 'typical' (similar in meaning).
'a'+'typical'='ATYPICAL'
(Other definitions for atypical that I've seen before include "Not as expected" , "'Abnormal, aberrant (8)'" , "Uncharacteristic" , "out of character" , "Not conforming to a norm or average" .)