Boastful talk securing a post (8)
I believe the answer is:
baluster
'post' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for baluster that I've seen before include "post" , "Rail hold-up" , "column" , "This could hold up rail" , "pillar of support" .)