Artilleryman given huge sum, heading off stronger (10)
I believe the answer is:
bombardier
'artilleryman' is the definition.
(thesaurus)
'huge sum heading off stronger' is the wordplay.
'huge sum' becomes 'bomb' (bomb can mean a huge sum of money).
'heading off' means to remove the first letter.
'stronger' becomes 'hardier' (hardy can mean fit or strong).
'hardier' with its first letter removed is 'ardier'.
'bomb'+'ardier'='BOMBARDIER'
'given' acts as a link.
(Other definitions for bombardier that I've seen before include "NCO" , "Royal Artillery soldier" , "Artillery rank" .)