Modifiers matching difficulty:

• psychological,
• smaller,
• emotional,
• experienced,
• severe,
• nutritional,
• serious,
• past,
• unexpected,
• related,
• technological,
• common,
• home,
• physical,
• personal,
• psychiatric,
• developmental,
• respiratory,
• sexual,
• everyday,
• unforeseen,
• underlying,
• ongoing,
• important,
• extra,
• environmental,
• stable,
• concurrent,
• motor,
• financial,
• regulation,
• cognitive,
• behavioural,
• neurological,
• hormonal,
• academic,
• stressful,
• computational,
• educational,
• perceptual,
• temporary,
• domestic,
• mathematical,
• prevalent,
• extraneous,
• reproductive,
• progressive,
• subjective,
• acute,
• administrative,
• mechanical,
• sensory,
• major,
• operational,
• technical,
• experimental,
• structural,
• economic,
• extreme,
• natural,
• parental,
• external,
• local,
• maternal,
• significant,
• internal,
• real,
• leaning,
• surgical,
• chronic,
• visual,
• particular,
• possible,
• logistical,
• somatic,
• functional,
• social,
• mental,
• basic,
• commercial,
• minor,
• persistent,
• single,
• typical,
• secondary,
• linguistic,
• legal,
• periodic,
• neuropsychiatric,
• habitual,
• behavioral,
• spiritual,
• special,
• practical,
• traditional,
• unanticipated,
• interpersonal,
• clinical,
• anatomical,
• invisible,
• unusual,
• conceptual,

Simple categories matching possible:

• infection,
• cause,
• reaction,
• fuel,
• lesion,
• extra,
• contaminant,
• defect,
• use,
• pollutant,
• activity,
• condition,
• work,
• theme,
• inflammation,
• acid,
• rodent,
• organism,
• catalyst,
• catastrophe,
• facility,
• event,
• error,
• precipitant,
• ingredient,
• residue,
• opposition,
• contamination,
• disorder,
• complication,
• difficulty,
• disease,
• form,
• material,
• mechanism,
• animal,
• antigen,
• sentence,
• state,
• impurity,
• disturbance,
• chemical,
• toxicant,
• specification,
• morbidity,
• motion,
• usage,
• target,
• interaction,
• group,
• agent,
• eruption,
• action,
• artifact,
• layer,
• metal,
• system,
• list,
• poison,
• bacteria,
• surface,
• virus,
• nexus,
• conflict,
• failure,
• danger,
• substrate,
• injury,
• evidence,
• disaster,
• solution,
• occurrence,
• thing,
• accident,
• volatile,
• development,
• career,
• malady,
• protease,
• problem,
• substance,
• place,
• entity,
• toxin,
• service,
• feature,
• prey,
• germ,
• modification,
• sport,
• allergen,
• means,
• parasite,
• transformation,
• emotion,
• procedure,
• change,
• incident,
• way,
• fluid,
• assistant,
• piece,
• area,
• symptom,
• precursor,
• illness,
• market,
• situation,
• hazard,
• request,
• entertainment,
• pathogen,
• intermediate,
• equipment,
• predator,
• process,
• abrasive,
• information,
• pathology,
• indication,
• syndrome,
• comfort,
• sector,