Naiveté shown at bar in Orange County by old US vice-president, losing the head (9)
I believe the answer is:
innocence
'naivete' is the definition.
(I know that innocence is a type of naivete)
'at bar in orange county by old us vice-president losing the head' is the wordplay.
'at' says to put letters next to each other.
'bar' becomes 'inn' (both can mean a drinking establishment).
'in orange county by old us' becomes 'oc' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'vice-president' becomes 'Pence' (Mike Pence).
'losing the head' means to remove the first letter.
'pence' with its initial letter removed is 'ence'.
'inn' next to 'oc' is 'innoc'.
'innoc'+'ence'='INNOCENCE'
'shown' is the link.
Can you help me to learn more?
(Other definitions for innocence that I've seen before include "Uncorrupted state" , "subject of Blake's songs" , "Freedom from guilt" , "Moral purity" , "Lack of guilt" .)