Modifiers matching formation:

• weak,
• geological,
• geologic,
• medium,
• nearby,
• tall,
• natural,
• geophysical,
• plastic,
• siliceous,
• strange,
• impermeable,
• political,
• social,
• stable,
• virtual,
• geographical,
• unusual,
• porous,
• spiritual,
• polygonal,
• common,
• geometric,
• impersonal,
• diverse,
• past,
• hollow,
• morbid,
• underground,
• offer,
• structural,
• artistic,
• hard,
• permeable,
• smaller,
• moving,
• larger,
• abrasive,
• mental,
• galactic,
• cultural,
• igneous,
• strong,
• traditional,
• pedestrian,
• unstable,
• key,
• cambrian,
• conceptual,
• major,
• large,
• rocky,
• sticky,
• dense,
• special,
• intricate,
• personal,
• exterior,
• glacial,
• surrounding,
• individual,
• typical,
• pathologic,
• impervious,
• solid,
• underwater,
• earthen,
• softer,
• subsurface,
• historical,
• ideological,
• tropical,
• active,
• organic,
• particular,
• unique,
• defensive,
• regular,
• territorial,
• geographic,
• internal,
• pointed,
• molecular,
• undesirable,
• discrete,
• small,
• acid,
• ancient,
• quaternary,
• spatial,
• popular,
• volcanic,
• uniform,
• military,
• christian,
• national,
• interesting,
• star,
• formal,
• salt,
• separate,
• symbolic,
• beautiful,
• sedimentary,
• thick,
• elastic,
• massive,
• driving,
• monolithic,
• rare,
• impressive,
• deep,
• sacred,
• up,
• unconsolidated,
• harder,
• vertical,
• standard,
• crystalline,
• coastal,
• calcareous,
• homogeneous,
• soft,
• conical,
• complex,
• organized,

Simple categories matching hollow:

• piece,
• viscus,
• object,
• article,
• ware,
• structure,
• sphere,
• cavity,
• panel,
• shape,
• thing,
• glass,
• dish,
• item,
• part,
• section,
• handgrip,
• container,
• form,
• feature,
• surface,
• utensil,
• ball,
• bird,
• carrier,
• ceiling,
• product,
• tree,
• formation,
• pipe,
• body,
• organ,
• needle,
• vessel,
• organs,
• instrument,
• plant,
• bone,
• tissue,
• construction,
• reed,
• protuberance,
• shaft,
• fiber,
• assembly,
• conduit,
• cylinder,
• space,
• region,
• pole,
• receptacle,
• wall,
• polyhedron,
• stem,
• material,
• shell,
• wood,
• beads,
• passage,
• viscera,
• glassware,
• bones,
• jewelry,
• tubing,
• particle,
• area,
• tube,
• fibre,
• implement,
• component,
• animal,