Woodcutter's commercials on radio (4)
I believe the answer is:
adze
'woodcutter's' is the definition.
(axe-like tool)
'commercials on radio' is the wordplay.
'commercials' becomes 'ads' (advertisements).
'on radio' shows a homophone (sound like).
'ads' sounds like 'ADZE'.
(Other definitions for adze that I've seen before include "Carpenter's shaping tool" , "One cuts" , "Carpenter's tool sound mathematically capable" , "cutter" , "Wood-shaping tool" .)