Orange car somehow suggests overconfidence (9)
I believe the answer is:
arrogance
'overconfidence' is the definition.
(thesaurus)
'orange car somehow' is the wordplay.
'somehow' indicates an anagram.
'orange'+'car'='orangecar'
'orangecar' is an anagram of 'ARROGANCE'.
'suggests' is the link.
(Other definitions for arrogance that I've seen before include "Conceitedness" , "Offensive sense of superiority" , "Overbearing attitude of pride and insolence" , "Overweening self-importance" , "Hauteur" .)