Cry about boxer's last fight (5)
I believe the answer is:
brawl
'fight' is the definition.
(I know that brawl is a type of fight)
'cry about boxer's last' is the wordplay.
'cry' becomes 'bawl' (synonyms).
'about' indicates putting letters inside.
'last' indicates one should take the final letters.
The final letter of 'boxer' is 'r'.
'bawl' enclosing 'r' is 'BRAWL'.
(Other definitions for brawl that I've seen before include "I'd punt for a learned person" , "Noisy crowd fight" , "Abounding" , "dispute" , "Affray" .)