Launching event broadcast live during month (7)
I believe the answer is:
javelin
'launching event' is the definition.
(athletic event)
'broadcast live during month' is the wordplay.
'broadcast' is an anagram indicator (letters scattered or cast around).
'during' means one lot of letters goes inside another.
'month' becomes 'Jan' (Jan is short for January).
'live' is an anagram of 'veli'.
'veli' inserted inside 'jan' is 'JAVELIN'.
(Other definitions for javelin that I've seen before include "Light spear" , "It's thrown in a field event" , "Type of spear" , "Athletics missile" , "Long spear" .)