Regularly downplays exclusive (4)
I believe the answer is:
only
'exclusive' is the definition.
(thesaurus)
'regularly downplays' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternate letters of 'downplays' are 'ONLY'.
(Other definitions for only that I've seen before include "And nothing more; sole" , "Solely, lone" , "Single, solitary" , "Merely; single" , "And no one else" .)