Complete
Perfect, Perfection, Completeness
noun, な adjective, の adjective
When something is all perfect it is complete. Not only that, but it's perfect (because it's ALL perfect, not just partially so).
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
君には完全に負けたよ。
You totally beat me.
残念ながら、コウイチには完全なアリバイがあります。
Unfortunately, Koichi has a perfect alibi.
私はあなたの意見に完全に同意します。
I completely agree with your opinion.