Trade in lead, possibly (4)
I believe the answer is:
deal
'trade in' is the definition.
(thesaurus)
'lead possibly' is the wordplay.
'possibly' is an anagram indicator.
'lead' is an anagram of 'DEAL'.
(Other definitions for deal that I've seen before include "Softwood - business transaction" , "Sawn wood" , "Treat" , "Board" , "Give out (cards)" .)