Post that supports article probing loud and aggressive speech (8)
I believe the answer is:
baluster
'post that supports' is the definition.
'article probing loud and aggressive speech' is the wordplay.
'article' becomes 'a' (indefinite article).
'probing' is an insertion indicator (probe can mean to make a hole in).
'loud and aggressive speech' becomes 'bluster'.
'a' inserted into 'bluster' is 'BALUSTER'.
(Other definitions for baluster that I've seen before include "pillar of support" , "One of a number of closely spaced supports for a railing" , "This could hold up rail" , "Pillar supporting staircase rail" , "post" .)