Modifiers matching obstacle:

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

Simple categories matching advanced:

• material,
• science,
• option,
• means,
• biotechnology,
• algorithm,
• stage,
• group,
• robot,
• modality,
• machinery,
• imaging,
• subject,
• mathematics,
• topic,
• class,
• illness,
• technology,
• fibre,
• operator,
• weaponry,
• work,
• hardware,
• synthesis,
• disease,
• processor,
• field,
• discipline,
• structure,
• whale,
• corporation,
• calculation,
• condition,
• fuel,
• degree,
• program,
• institution,
• calculator,
• metal,
• image,
• medium,
• defense,
• care,
• theory,
• product,
• complication,
• theme,
• power,
• plate,
• area,
• mode,
• component,
• test,
• job,
• container,
• concept,
• information,
• works,
• sector,
• practice,
• massage,
• cancer,
• use,
• machine,
• operations,
• artifact,
• dressing,
• species,
• insect,
• rendering,
• force,
• control,
• attribute,
• nation,
• system,
• instrumentation,
• widget,
• study,
• function,
• resource,
• knowledge,
• weapon,
• therapy,
• ceramics,
• strategy,
• mammal,
• course,
• movement,
• rating,
• method,
• animal,
• organism,
• technique,
• chemistry,
• service,
• optimization,
• behavior,
• skill,
• world,
• mechanism,
• reasoning,
• coating,
• content,
• doctorate,
• alloy,
• industry,
• education,
• sport,
• thing,
• credit,
• effect,
• treatment,
• equipment,
• apparatus,
• physics,
• issue,
• procedure,
• unit,
• instrument,
• measure,
• fiber,
• network,
• installation,
• tumor,
• math,
• stuff,
• project,
• medicine,
• law,
• filter,
• devices,
• appliance,
• region,
• vessel,
• task,
• obstacle,
• intervention,
• profession,
• surgery,
• training,
• vehicle,
• plot,
• application,
• tool,
• school,
• substrate,
• physiology,
• country,
• stroke,
• maneuver,
• instruction,
• process,
• spread,
• surface,
• activity,
• detector,
• aircraft,
• trick,
• database,
• characteristic,
• feature,
• searcher,
• building,
• motor,
• item,
• society,
• facility,
• shape,
• pattern,
• sensor,