A technical term from Levitical regulations for dealing with houses infected with spreading mold or mildew. When discoloration reappeared after initial treatment, the priest ordered all interior walls scraped and the contaminated plaster dumped outside the city in an unclean place. This radical cleansing protected community health while teaching spiritual lessons about sin's pervasiveness - like mildew, it requires thorough removal, not surface treatment. The detailed procedures show how Israel's worship, health, and daily life formed an integrated whole. Physical cleanliness and spiritual purity reinforced each other in a society where God's presence dwelt among his people.