Boxer about to get into company making cloth (6)
I believe the answer is:
calico
'cloth' is the definition.
(calico is a kind of cloth)
'boxer about to get into company' is the wordplay.
'boxer' becomes 'ali' (Muhammad Ali).
'about' becomes 'c' (abbreviation for 'circa'**).
'to get into' means one lot of letters goes inside another.
'company' becomes 'co' (abbreviation).
'ali'+'c'='alic'
'alic' put inside 'co' is 'CALICO'.
'making' is the link.
(Other definitions for calico that I've seen before include "Unbleached sixteen down cloth" , "Coarse printed cotton cloth" , "Plain cotton cloth, white or unbleached" , "Given material for dress" , "White cotton fabric" .)