'Unholy' in the Bible

Now Nadab and Abihu, the sons of Aaron, took their respective [ceremonial] censers, put fire in them, placed incense on it and offered strange (unauthorized, unacceptable) fire before the Lord, [an act] which He had not commanded them to do.

and to make a distinction and recognize a difference between the holy (sacred) and the common (profane), and between the [ceremonially] unclean and the clean;