Drop broadcast for match (4)
I believe the answer is:
sync
'match' is the definition.
(I've seen this in another clue)
'drop broadcast' is the wordplay.
'drop' becomes 'sink' (synonyms).
'broadcast' shows a homophone (sound like) (how the word might sound on the radio or TV).
'sink' sounds like 'SYNC'.
'for' is the link.
(Other definitions for sync that I've seen before include "Togetherness (of sound and picture, say)" , "Relationship when things occur at the same time" , "Agreement in time" , "In which one's matching" , "Unison (abbrev.)" .)