Simple categories matching proper:

• tool,
• undergarment,
• material,
• instruction,
• substrate,
• quality,
• exercise,
• precaution,
• equipment,
• fluid,
• metal,
• condition,
• information,
• record,
• installation,
• underclothes,
• medium,
• expense,

Members with property proper:

• paperboard,
• camisole,
• polyester,
• pencil,
• slip,
• sponge,
• silicon,
• bone_dust,
• adult_diaper,
• tartan,
• bra,
• steel_pipe,
• ruler,
• papers,
• yoga,
• crinoline,
• gold_au,
• cork,
• aerobics,
• shale,
• hoop_skirt,
• scaffolding,
• police_report,
• gold,
• plastic_material,
• liquid_metal,
• copper_alloy,
• steel_shape,
• underwear,
• paper,
• builder_felt,
• receipt_book,
• rag,
• copper,
• report,
• postage,
• pen,
• sugar,
• level,
• problem_report,
• metal,
• silicon_nitride,
• bentonite,
• metal_crampon,
• freedom,
• grid_paper,
• book,
• bucket,
• diet_book,
• right_size,
• cardboard,
• wood,
• silicon_wafer,
• steel,
• prescription_book,
• case_book,
• polyethylene,
• guard,
• plain_paper,