Diverted by deliberate addition to commercial (6)
I believe the answer is:
amused
'diverted' is the definition.
(synonyms)
'deliberate addition to commercial' is the wordplay.
'deliberate' becomes 'muse' (I've seen this in another clue).
'addition to' is an insertion indicator.
'commercial' becomes 'ad' (abbreviation for advertisement).
'muse' put into 'ad' is 'AMUSED'.
'by' is the link.
(Other definitions for amused that I've seen before include "Medusa (anag)" , "was entertaining" , "Kept someone entertained" , "Provoked mirth in" , "Mildly diverted or entertained" .)