Overweeningness (6)
I believe the answer is:
hubris
'overweeningness' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for hubris that I've seen before include "Overbearing pride or self-confidence" , "The pride that goes before a fall" , "feeling of superiority" , "Arrogant pride, from the Greek" , "Excessive pride" .)