unclean
a person or thing that did not meet certain conditions. Something unclean could not be part of religious services. God set the conditions for people and things to be included in worshiping him. People who were unclean could be cleansed. Then they could worship again. To be unclean was a symbol for not being spiritually pure.
Leviticus 11 - 15
The sacrifice of Jesus makes his followers spiritually clean. So they do not follow the Old Testament laws about unclean conditions.