The abstract noun "uncleanness" can be stated as an adjective. Alternate translation: "if he touches anything that makes a person unclean" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
Something that Yahweh has declared unfit for a person to touch or eat is spoken of as if it were physically unclean. (See: [[rc://en/ta/man/translate/figs-metaphor]])