Small chicken and light boxer (6)
I believe the answer is:
bantam
'small chicken and light boxer' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for bantam that I've seen before include "Small chicken - small soldier" , "Boxing weight or domestic fowl" , "Nab mat (anag)" , "small quarrelsome person" , "Very small - batman (anag)" .)