Modifiers matching barrier:

• physical,
• structural,
• effective,
• solid,
• confining,
• residential,
• positive,
• nonstructural,
• protective,
• technical,
• larger,
• chemical,
• visual,
• artificial,
• endothelial,
• visible,
• basic,
• permanent,
• up,
• continuous,
• new,
• natural,
• under,
• thin,
• real,
• level,
• regulatory,
• porous,
• impermeable,
• nonmetallic,
• old,
• typical,
• environmental,
• fixed,
• permeable,
• conventional,
• geological,
• rigid,
• concrete,
• low,
• symbolic,
• linear,
• home,
• opaque,
• architectural,
• disposable,
• upright,
• light,
• logical,
• simple,
• minor,
• horizontal,
• animal,
• physiological,
• normal,
• hydraulic,
• static,
• small,
• defined,
• metallic,
• external,
• major,
• coastal,
• exterior,
• reliable,
• vertical,
• mechanical,
• institutional,
• high,
• flexible,
• mobile,
• over,
• erect,
• passive,
• moving,
• removable,
• impenetrable,
• secure,
• hard,
• thick,
• significant,
• molecular,
• penetrating,
• behavioural,
• immovable,
• accessible,
• temporary,
• conductive,
• resistant,
• moveable,
• stable,
• multiple,
• suitable,
• durable,
• surrounding,
• outdoor,

Simple categories matching nonmetallic:

• atom,
• material,
• mineral,
• polymer,
• dust,
• tool,
• container,
• compound,
• surface,
• substance,
• substrate,
• matrix,
• component,
• inclusion,
• object,
• liquid,
• core,
• commodity,
• deposit,
• part,
• carcinogen,
• connection,
• particulate,
• contaminant,
• weapon,
• gem,
• matter,
• pipe,
• body,
• instrument,
• line,
• medium,
• solid,
• element,
• metal,
• glasses,
• residue,
• particle,
• fiber,
• structure,
• agent,
• item,
• coating,
• facility,
• system,
• barrier,