adikia

This is the built-in opposite of righteousness. Where righteousness is being and doing what is right, this word names the failure to be or do right, and the New Testament sets the two side by side again and again (weapons of unrighteousness against weapons of righteousness, love that refuses to celebrate wrongdoing but rejoices with the truth). It is a wide word: English Bibles reach for "unrighteousness", "wickedness", "iniquity", "injustice", and "plain wrong", all trying to catch the same idea from different angles.

Most often it names a quality or condition rather than one act: the whole moral bent of a person or an age that is set against God and against the truth. It is the state Paul says God's anger is revealed against, the thing people are said to be full of, the darkness that stands opposed to the light of truth. Because it is so broad, it can also point to a single concrete wrong done to someone, especially in the plural, where it comes close to "iniquities" or "misdeeds".

A distinct habit of speech grows out of the same idea. Writers use the phrase "of unrighteousness" to brand a person or thing as crooked or dishonest:

• the dishonest manager
• the unjust judge
• money gained the wrong way

Here the word is not describing an abstract force so much as labeling something as bent, in a Hebrew-flavored turn of phrase that English usually smooths out to a simple adjective like "dishonest" or "ill-gotten".