Utterly destroy song? Rubbish! (3,5)
I believe the answer is:
lay waste
'utterly destroy' is the definition.
'lay waste' can be an answer for 'destroy' (I've seen this in another clue). I'm not certain of the 'utterly' bit.
'song? rubbish' is the wordplay.
'song?' becomes 'lay' (poetic term for a song).
'rubbish' becomes 'waste' (I've seen this before).
'lay'+'waste'='LAY WASTE'
Can you help me to learn more?
(Other definitions for lay waste that I've seen before include "Completely destroy (something)" , "Destroy and ruin an area" , "Destroy or ruin, demolish" , "Destroy or ruin as in war" , "Destroy, leave in ruins" .)