'Unclean' in the Bible

These searched among their ancestral registration, but they could not be located; therefore they were considered unclean and excluded from the priesthood.

which You have commanded by Your servants the prophets, saying, ‘The land which you are entering to possess is an unclean land with the uncleanness of the peoples of the lands, with their abominations which have filled it from end to end and with their impurity.