Modifiers matching obstacle:

• private,
• natural,
• passive,
• physical,
• psychological,
• fixed,
• outdoor,
• vertical,
• architectural,
• special,
• size,
• multiple,
• additional,
• high,
• artificial,
• difficult,
• dangerous,
• opaque,
• creative,
• permanent,
• environmental,
• penetrating,
• large,
• soft,
• unusual,
• small,
• rectangular,
• concrete,
• linear,
• solid,
• unmovable,
• mechanical,
• local,
• rigid,
• dense,
• single,
• extensive,
• common,
• geological,
• overhead,
• hazardous,
• typical,
• tall,
• wooden,
• clear,
• adjacent,
• advanced,
• impenetrable,
• rural,
• porous,
• everyday,
• urban,
• tricky,
• stationary,
• working,
• external,
• coming,
• elevated,
• institutional,
• practical,
• simple,
• thick,
• visual,
• distant,
• removable,
• nearby,
• dynamic,
• world,
• moving,
• underground,
• interfering,
• over,
• static,
• structural,
• narrow,
• movable,
• geographic,

Simple categories matching overhead:

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