noun, な adjective, の adjective
A not law is something that's against the law. It's illegal or unlawful.
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.
None of the Tofugu workers know about the illegal black-market transactions that Viet does.
How many illegal aliens do you think there are in the U.S. at the moment?
We can’t use evidence obtained through an unlawful search at the court.