Dealers starred in play (7)
I believe the answer is:
traders
'dealers' is the definition.
(I know this)
'starred in play' is the wordplay.
'in play' is an anagram indicator (letters play around).
'starred' with letters rearranged gives 'TRADERS'.
(Other definitions for traders that I've seen before include "businessmen" , "Dealers" , "Sellers" .)