Relay comprehensive actors (9)
I believe the answer is:
broadcast
'relay' is the definition.
(thesaurus)
'comprehensive actors' is the wordplay.
'comprehensive' becomes 'broad' (similar in meaning).
'actors' becomes 'cast' (group of actors).
'broad'+'cast'='BROADCAST'
(Other definitions for broadcast that I've seen before include "Transmit (programme)" , "Sow" , "distributed by hand" , "Send out by radio or television" , "Transmit over airwaves" .)