Bill interrupts peaceful song (8)
I believe the answer is:
serenade
'song' is the definition.
(I've seen this before)
'bill interrupts peaceful' is the wordplay.
'bill' becomes 'ad' (advertisement stuck on wall).
'interrupts' is an insertion indicator.
'peaceful' becomes 'serene' ('serene' can be similar in meaning to 'peaceful').
'ad' going within 'serene' is 'SERENADE'.
(Other definitions for serenade that I've seen before include "Suitor's song" , "Evening music (played outside woman's house)" , "Musical performance, under a lady's window?" , "Song to a lover" , "Lover's song" .)