Fighter in soup, what a mess! (8)
I believe the answer is:
southpaw
'fighter' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'soup what a mess' is the wordplay.
'a mess' is an anagram indicator.
'soup'+'what'='soupwhat'
'soupwhat' is an anagram of 'SOUTHPAW'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for southpaw that I've seen before include "Left-hander" , "Boxer who leads with the right hand" , "One using left hand" , "Left-handed fighter" , "Boxer who leads with right fist" .)