As opposed to a commercial jingle (7)
I believe the answer is:
adverse
'as opposed' is the definition.
'adverse' can be an answer for 'opposed' (I've seen this in another clue). I'm not sure about the 'as' bit.
'commercial jingle' is the wordplay.
'commercial' becomes 'ad' (abbreviation for advertisement).
'jingle' becomes 'verse' (I can't justify this - if you can you should believe this answer much more).
'ad'+'verse'='ADVERSE'
'to a' acts as a link.
Can you help me to learn more?
(Other definitions for adverse that I've seen before include "Unfavourable to evaders" , "Opposed - inauspicious - opposite" , "Inopportune" , "In an opposing direction" , "Opposed to or unfavourable" .)