Modifiers matching difficulty:

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

Simple categories matching psychological:

• quality,
• use,
• process,
• abnormality,
• state,
• condition,
• energy,
• disorder,
• variable,
• block,
• problem,
• domain,
• characteristic,
• practice,
• development,
• attribute,
• makeup,
• aggression,
• evaluation,
• event,
• feature,
• property,
• trait,
• distress,
• task,
• obstacle,
• difficulty,
• trouble,
• disposition,
• area,
• principle,
• consequence,
• mistreatment,
• nature,
• behavior,
• form,
• tendency,
• mechanism,
• aberration,
• limitation,
• connection,
• error,
• complication,
• care,
• adaptation,
• science,
• closeness,
• bias,
• capability,
• instrument,
• motivation,
• pain,
• phenomenon,
• stage,
• discomfort,
• dimension,
• harm,
• feeling,
• test,
• change,
• function,
• support,
• measurement,
• impairment,
• study,
• injury,
• concern,
• skill,
• motive,
• manipulation,
• abuse,
• experience,
• stress,
• education,
• perception,
• ailment,
• content,
• complaint,
• discipline,
• inquiry,
• faculty,
• method,
• research,
• defence,
• topic,
• maturity,
• system,
• response,
• control,
• model,
• harassment,
• fiction,
• intervention,
• strength,
• activity,
• cause,
• terms,
• resource,
• conflict,
• knowledge,
• inertia,
• abstraction,
• morbidity,
• technique,
• drive,
• reward,
• factor,
• trauma,
• hazard,
• defense,
• maltreatment,
• values,
• capacity,
• component,
• ability,
• pressure,
• issue,
• reaction,
• force,
• teaching,
• product,
• disease,
• emotion,
• ill,
• aspect,
• pleasure,
• notion,
• malady,
• status,
• crime,
• idea,
• help,
• exercise,
• demand,
• procedure,
• attitude,
• strain,
• belief,
• level,
• play,
• symptom,
• power,
• work,
• service,
• theory,
• treatment,
• entity,
• concept,
• damage,
• perturbation,
• measure,
• disturbance,
• behaviour,
• therapy,
• impact,
• space,
• situation,
• project,
• illness,
• analyst,
• structure,
• benefit,