Modifiers matching formation:

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

Simple categories matching impervious:

• conveyance,
• surface,
• item,
• material,
• flooring,
• glove,
• fabric,
• layer,
• envelope,
• stone,
• object,
• construction,
• clothing,
• substance,
• area,
• container,
• subsoil,
• nature,
• substrate,
• covering,
• concrete,
• soil,
• formation,
• paint,
• structure,
• paving,
• catchment,
• rock,
• land,
• tile,
• cover,
• film,
• membrane,
• coating,
• receptacle,