Modifiers matching obstruction:

• electrical,
• physical,
• up,
• dense,
• permanent,
• removable,
• metal,
• clear,
• adjacent,
• local,
• temporary,
• vertical,
• solid,
• larger,
• cooler,
• hydraulic,
• simple,
• horizontal,
• visual,
• artificial,
• taller,
• raised,
• current,
• typical,
• nearby,
• featureless,
• overhead,
• subsurface,
• isolated,
• common,
• geographic,
• multiple,
• additional,
• urethral,
• significant,
• irregular,
• level,
• rigid,
• relevant,
• smaller,
• impenetrable,
• internal,
• indoor,
• upright,
• insurmountable,
• virtual,
• hidden,
• hazardous,
• short,
• hard,
• visible,
• bigger,
• surrounding,
• fixed,
• major,
• unusual,
• under,
• opaque,
• outdoor,
• tall,
• topical,
• elongated,
• over,
• external,
• immovable,
• mechanical,
• terrestrial,
• small,
• nasal,
• layer,
• spatial,
• large,
• discrete,
• past,
• lateral,
• lighted,
• structural,
• environmental,
• linear,
• low,
• movable,
• natural,
• minor,
• underwater,
• underground,

Simple categories matching overhead:

• structure,
• clearance,
• activity,
• light,
• information,
• hazard,
• fixture,
• substrate,
• industry,
• motion,
• lighting,
• sport,
• capital,
• expense,
• surface,
• function,
• obstruction,
• installation,
• obstacle,
• foundation,
• work,
• action,
• athletics,
• protection,
• projection,
• construction,
• cost,
• line,
• predator,
• system,
• contamination,
• movement,
• covering,
• operations,
• athlete,
• component,
• object,
• radiation,
• message,
• operation,
• area,
• cover,
• expenditure,
• vehicle,
• support,
• solution,
• location,
• resource,
• door,
• wire,
• item,
• charge,
• lamp,
• layer,