Oprah broadcast for Marx (5)
I believe the answer is:
harpo
'for marx' is the definition.
(Harpo Marx)
'oprah broadcast' is the wordplay.
'broadcast' is an anagram indicator (letters scattered or cast around).
'oprah' is an anagram of 'HARPO'.
(Other definitions for harpo that I've seen before include "Silent Marx brother" , "one from family of comedians" , "speechless brother" , "The mute Marx Brother" , "brother who never speaks" .)