Savage insult by Iran - a mistake (9)
I believe the answer is:
barbarian
'savage' is the definition.
(I know that savage can be written as barbarian)
'insult by iran a mistake' is the wordplay.
'insult' becomes 'barb' (I've seen this in another clue).
'by' is a charade indicator (letters next to each other).
'mistake' indicates an anagram.
'iran'+'a'='irana'
'irana' anagrammed gives 'arian'.
'barb'+'arian'='BARBARIAN'
(Other definitions for barbarian that I've seen before include "wild fellow" , "outlandish foreigner" , "uncivilised man" , "Uncultured, brutish" , "Savage - rugby player" .)