Struck down, he gave a bit of a bellow (4)
I believe the answer is:
abel
'struck down he' is the definition.
'Abel' can be an answer for 'he'. I am unsure of the 'struck down' bit.
'a bit of a bellow' is the wordplay.
'bit of a bellow' becomes 'bel' (I can't justify this - if you can you should believe this answer much more).
'a'+'bel'='ABEL'
'gave' is the link.
Can you help me to learn more?
(Other definitions for abel that I've seen before include "The first murderee?" , "Cain's 11" , "Adamson" , "Victim of murderer" , "fellow killed by brother" .)