Woodcutter's commercials for broadcast (4)
I believe the answer is:
adze
'woodcutter's' is the definition.
(axe-like tool)
'commercials for broadcast' is the wordplay.
'commercials' becomes 'ads' (advertisements).
'for broadcast' shows a homophone (sound like).
'ads' sounds like 'ADZE'.
(Other definitions for adze that I've seen before include "Tool for shaping large pieces of wood" , "Tool, sounds like sums" , "Axe-like tool" , "Woodworking tool" , "Daze with a sort of axe" .)