Who did something dishonest?
There was unauthorized access from China and all of Tofugu's social media accounts were hacked.
My aunt always talks about her personal acts of injustice and deception.
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.
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.