Who's put out about a boxer? (8)
I believe the answer is:
southpaw
'boxer?' is the definition.
(term for a left-handed boxer)
'who's put out about a' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'about' indicates putting letters inside.
'whos'+'put'='whosput'
'whosput' with letters rearranged gives 'southpw'.
'southpw' going around 'a' is 'SOUTHPAW'.
(Other definitions for southpaw that I've seen before include "One using left hand" , "Man with gloves on" , "A left-handed boxer who leads with the right" , "Boxer leading with right hand" , "one leading from the right" .)