Commercials broadcast for bladed tool (4)
I believe the answer is:
adze
'bladed tool' is the definition.
(I've seen this in another clue)
'commercials broadcast' is the wordplay.
'commercials' becomes 'ads' (ad is short for advert).
'broadcast' shows a homophone (sound like) (how the word might sound on the radio or TV).
'ads' sounds like 'ADZE'.
'for' acts as a link.
(Other definitions for adze that I've seen before include "Tool, sounds like sums" , "tool for carpenter" , "Something with sharp edge" , "One cuts" , "Timber-shaping tool" .)