Savaging idiot repeatedly in letter, I state (9-13)

'state' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.

'savaging idiot repeatedly in letter i' is the wordplay.
I cannot quite see how this works, but
'idiot' could be 'ass' (both can mean a stupid person) and 'ass' is present in the answer.
'in' is within the answer.
'letter' could be 'character' (written character) and 'character' is found in the answer.
'i' could be 'a' and 'a' is located in the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?