unlawful

Definition:

The terms "unlawful" and "not lawful" are used to describe actions that break a law.

In the New Testament, the term "unlawful" is not only used to refer to breaking God's laws, but also often refers to breaking Jewish manmade laws.
Over the years, the Jews added to the laws that God gave to them. The Jewish leaders would call something "unlawful" if it did not conform to their manmade laws.
When Jesus and his disciples were picking grain on a Sabbath day, the Pharisees accused them of doing something "unlawful" because it was breaking the Jewish laws about not working on that day.
When Peter stated that eating unclean foods was "unlawful" for him, he meant that if he ate those foods he would be breaking the laws God had given the Israelites about not eating certain foods.

This term should be translated using a word or expression that means, "not lawful" or "lawbreaking."
Other ways to translate "unlawful" could be, "not permitted" or "not according to God's law" or "not conforming to our laws."
The expression "against the law" has the same meaning as "unlawful."