Broadcast second conclusion (4)
I believe the answer is:
send
'broadcast' is the definition.
(I know that broadcast can be written as send)
'second conclusion' is the wordplay.
'second' becomes 's' (common abbreviation).
'conclusion' becomes 'end' (something's conclusion is its end).
's'+'end'='SEND'
(Other definitions for send that I've seen before include "Transmit; post" , "broadcast" , "Consign" , "and 2: Advise" , "Cause to go for" .)