Changing Iran is a top objective (10)
I believe the answer is:
aspiration
'objective' is the definition.
(thesaurus)
'changing iran is a top' is the wordplay.
'changing' indicates an anagram.
'iran'+'is'+'a'+'top'='iranisatop'
'iranisatop' with letters rearranged gives 'ASPIRATION'.
(Other definitions for aspiration that I've seen before include "goal" , "Ambition" , "Hope" , "With which to announce Hammers' first" , "Dream" .)