Attack boys in blue suit (3,3,4)
I believe the answer is:
fit the bill
'blue suit' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'attack boys' is the wordplay.
'attack' becomes 'fit' (fit is a kind of attack).
'boys' becomes 'thebill' (I can't explain this - if you can you should give a lot more credence to this answer).
'fit'+'thebill'='FIT THE BILL'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for fit the bill that I've seen before include "serve well" , "Be suitable" , "What police tailors might do" , "finish off some taxidermy?" .)