Modifiers matching obstacle:

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

Simple categories matching unmovable:

• obstacle,
• surface,
• thing,
• object,