Such bombast will get a bighead a bad result (7)
I believe the answer is:
bluster
'such bombast' is the definition.
'bluster' can be an answer for 'bombast' (thesaurus). I'm not sure about the 'such' bit.
'a bighead a bad result' is the wordplay.
'a bighead' becomes 'b' (the head letter of 'big').
'a bad' indicates anagramming the letters.
'result' is an anagram of 'luster'.
'b'+'luster'='BLUSTER'
'will get' acts as a link.
Can you help me to learn more?
(Other definitions for bluster that I've seen before include "Talk aggressively with empty threats" , "Braggadocio" , "Butlers given to aggressive, empty talk" , "Empty boasting" , "Talk aggressively to little or no effect" .)