It’s annoying, and I ultimately bluster and yell when holding it (8)
I believe the answer is:
irritant
'it's annoying' is the definition.
(I've seen this before)
'i ultimately bluster and yell when holding it' is the wordplay.
'ultimately' indicates one should take the final letters.
'and' is a charade indicator (letters next to each other).
'yell' becomes 'rant' (rant can mean to yell or shout).
'when holding' indicates putting letters inside.
The last letter of 'bluster' is 'r'.
'rant' enclosing 'it' is 'ritant'.
'i'+'r'+'ritant'='IRRITANT'
'and' acts as a link.
(Other definitions for irritant that I've seen before include "Something that causes annoyance and bad temper" , "Something that chafes or annoys" , "Source of continual annoyance" , "Annoying thing" , "Cause of itch" .)