Injustice, Dishonest, Unauthorized
noun, な adjective
When you have something that's not correct, you have no justice. In fact, you have injustice. Just imagine yourself being put in an unjust situation, and think about how not correct it is. It's probably dishonest and unauthorized too.
ふせい
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.
これは不正サイトです。
This is an unauthorized site.
大切なデータに不正なアクセスがあった。
There was unauthorized access to important data.
不正にログインがありました。
There was an unauthorized login.