System Iranian got so wrong (12)
I believe the answer is:
organisation
'system' is the definition.
(I've seen this before)
'iranian got so wrong' is the wordplay.
'wrong' indicates anagramming the letters.
'iranian'+'got'+'so'='iraniangotso'
'iraniangotso' is an anagram of 'ORGANISATION'.
(Other definitions for organisation that I've seen before include "System" , "Running" , "Systematic approach to tasks" , "concern" .)