Perfect
Flawless, Complete
な adjective
A perfect disc is flawless. It's just perfect.
As you may already know, in Japan the symbol ⭕ is used to mark correct answers. See how it looks like a perfect disc?
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own. Just remember that rendaku turns へき into ぺき.
私は日本の国歌を完璧に歌えます。
I can sing the Japanese national anthem perfectly.
このファイルを削除したら、これで準備は完璧です。
I'm going to delete these files, then I'll be completely ready.
日本語が完璧になりたい。
I want my Japanese to be flawless.