Modifiers matching headache:

• primary,
• paroxysmal,
• underlying,
• psychosomatic,
• common,
• chronic,
• severe,
• simple,
• vascular,
• secondary,
• major,
• debilitating,
• throbbing,
• persistent,
• episodic,
• serious,
• intense,
• recurrent,

Simple categories matching serious:

• abnormality,
• violation,
• illness,
• act,
• disease,
• assault,
• violence,
• charge,
• aberration,
• infection,
• passion,
• condition,
• phenomenon,
• crime,
• disruption,
• effort,
• form,
• professional,
• conflict,
• reaction,
• offense,
• infringement,
• injury,
• measure,
• incident,
• idea,
• allergy,
• game,
• disorder,
• addiction,
• offence,
• case,
• animal,
• symptom,
• sector,
• injustice,
• circumstances,
• entity,
• material,
• diversion,
• setback,
• bacteria,
• disaster,
• tale,
• malpractice,
• damage,
• constraint,
• profession,
• user,
• result,
• attack,
• system,
• sin,
• issue,
• state,
• agent,
• risk,
• surgery,
• item,
• casualty,
• zoonosis,
• attempt,
• arrhythmia,
• subject,
• danger,
• contagion,
• participation,
• works,
• document,
• upheaval,
• intervention,
• harm,
• work,
• flaw,
• song,
• virus,
• nature,
• misdeed,
• gathering,
• writing,
• emotion,
• weapon,
• wrongdoing,
• enterprise,
• theme,
• felony,
• scholar,
• cancer,
• happening,
• delinquent,
• behavior,
• indiscipline,
• threat,
• enjoyment,
• problem,
• phobia,
• trauma,
• operation,
• trouble,
• study,
• journal,
• defect,
• malfunction,
• accident,
• evil,
• loss,
• pains,
• stage,
• pathogen,
• title,
• failure,
• reader,
• calamity,
• wound,
• activity,
• complaint,
• manifestation,
• stimulant,
• story,
• morbidity,
• misfortune,
• malady,
• challenge,
• narcotic,
• blemish,
• grounds,
• status,
• complication,
• music,
• topic,
• larceny,
• matter,
• cause,
• end,
• handicap,
• sickness,
• discipline,
• point,
• mishap,
• promise,
• interaction,
• storm,
• behaviour,
• disturbance,
• transgression,
• malignancy,
• imperfection,
• headache,
• tendency,
• event,
• conduct,
• misconduct,
• development,
• penalty,
• application,
• pain,
• science,
• information,
• consequence,
• content,
• need,
• trait,
• mistake,
• endeavor,
• drama,
• action,
• harassment,
• situation,
• experience,
• substance,
• sanction,
• disability,
• program,
• occurrence,
• stuff,
• business,
• pathology,
• help,
• thing,
• infraction,
• abuse,
• hazard,
• forum,
• std,
• dance,
• error,
• drug,
• difficulty,
• ailment,
• occasion,
• procedure,
• misbehaviour,
• piece,
• ceremony,
• tumour,