Anonymity
Pseudonym
Hide your name for anonymity. There's lots of that here on the internet. In fact, you're probably using a pseudonym right now, aren't you? Yeah, you are. You can't hide THAT from me at least... uh... Ssssteve?
とくめい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
匿名で投書をしました。
I wrote a letter to the editor anonymously.