Modifiers matching impurity:

• biological,
• airborne,
• physical,
• harmless,
• unwanted,
• out,
• coarse,
• ordinary,
• up,
• reactive,
• unavoidable,
• microscopic,
• volatile,
• damaging,
• undesired,
• minor,
• harmful,
• nonpolar,
• small,
• homogeneous,
• dilute,
• heterogeneous,
• atmospheric,
• gaseous,
• lightweight,
• colloidal,
• micro,
• common,
• absorptive,
• particulate,
• organic,
• light,
• random,
• little,
• insoluble,
• initial,
• environmental,
• suspended,
• off,
• residual,
• hazardous,
• mobile,
• lighter,
• polar,
• anionic,
• minute,
• corrosive,
• ionic,
• natural,
• sticky,
• possible,
• solid,
• soluble,
• stubborn,
• foreign,
• visible,
• fluid,
• mental,
• mechanical,
• separate,
• smaller,
• fine,
• interfering,
• active,
• heavier,
• inorganic,
• dissolved,
• desirable,
• chemical,

Simple categories matching soluble:

• material,
• medium,
• substance,
• waste,
• impurity,
• sugar,
• part,
• precursor,
• polymer,
• salt,
• lubricant,
• compound,
• alkaloid,
• solute,
• polysaccharide,
• fiber,
• oligosaccharide,
• receptor,
• toxin,
• particle,
• tracer,
• saccharide,
• coagulant,
• alkane,
• pollutant,
• filler,
• carbohydrate,
• carbonyl,
• metal,
• oxide,
• concentration,
• rock,
• alcohol,
• fibre,
• hydroxide,
• hormone,
• oil,
• contaminant,
• chloride,
• starch,
• component,
• salicylate,
• fertiliser,
• amine,
• nitrate,
• metabolite,
• carrier,
• solid,
• stain,
• sweetener,
• antigen,
• stabilizer,
• element,
• residue,
• sulphate,
• food,
• starches,
• liquid,
• molecule,
• soil,
• fraction,
• system,
• dirt,
• formulation,
• beverage,
• constituent,
• nutrient,
• hydrocolloid,
• nickel,
• volatile,
• gas,
• matter,
• preparation,
• fluid,
• substrate,
• catalyst,
• resin,
• solvent,
• derivative,
• phenol,
• item,
• fertilizer,
• drug,
• adhesive,
• vitamin,
• chemical,
• powder,
• agent,
• portion,
• atom,
• mineral,
• gum,
• fuel,
• surfactant,
• hydrocarbon,
• group,
• antioxidant,
• pesticide,
• deposit,
• macromolecule,
• size,
• sulfate,
• entity,
• electrode,
• sulphide,
• fluoride,
• enzyme,
• protein,
• monomer,