Enter claim about commercial (10)
I believe the answer is:
mercantile
'commercial' is the definition.
('mercantile' can be similar in meaning to 'commercial')
'enter claim about' is the wordplay.
'about' indicates an anagram.
'enter'+'claim'='enterclaim'
'enterclaim' is an anagram of 'MERCANTILE'.
(Other definitions for mercantile that I've seen before include "related to business" , "Dealing with trade" , "Commercial" , "Relating to (overseas) trade" , "concerning trade" .)