How to permanently delete purchaced songs from iTunes cloud?
How do I permanently delete purchaced songs from iTunes?
iPhone 5s, iOS 8
Your subject and post ask two different questions.
To delete from your iTunes library - select the song, press the delete key.
You do not delete anything from iCloud. iCloud is a service that allows iTunes customers to redownload past purchases. They are not "stored" specifically for you in your own space. You simply are allowed to redownload them from iCloud if you choose to do so.