Supports and is clearly proud of oneself (6)
I believe the answer is:
struts
'supports' is the definition.
(strut is a kind of support)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for struts that I've seen before include "arrogant motions" , "Bars inserted into framework to strengthen it" , "parades with conscious pride" , "Walks proudly like peacock" , "Walks in pompous self-satisfied way" .)