Self-important and overbearing (8)
I believe the answer is:
arrogant
'self-important and overbearing' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for arrogant that I've seen before include "Overweening" , "Proud and contemptuous" , "Proud and overbearing, feeling superior" , "Haughty - imperious" , "Conceited, self-important" .)