Modifiers matching occurrence:

• weather,
• unplanned,
• natural,
• unforeseen,
• major,
• interesting,
• random,
• serious,
• significant,
• neurologic,
• damaging,
• dangerous,
• unexpected,
• meaningful,
• unusual,
• supernatural,
• unfortunate,
• possible,
• climatic,
• annual,
• common,
• small,
• unpredictable,
• recent,
• sudden,
• uncertain,
• geologic,
• transient,
• catastrophic,
• abnormal,
• deviant,
• motivational,
• political,
• physical,
• seasonal,
• strange,
• social,
• odd,
• local,
• rare,
• normal,
• terrifying,
• seismic,
• single,
• periodic,
• unanticipated,
• irregular,
• unforeseeable,
• commonplace,
• inanimate,
• outdoor,
• planned,
• routine,
• special,
• cosmic,
• awesome,
• miscellaneous,
• future,
• benign,
• simple,
• tragic,
• elemental,
• extraordinary,
• outside,
• historical,
• disruptive,
• criminal,
• disastrous,
• superficial,
• medical,
• dynamic,
• interactive,
• autonomic,
• neurological,
• ordinary,
• spontaneous,
• operational,
• undesirable,
• everyday,
• severe,
• negative,
• unlikely,
• devastating,
• discrete,
• infrequent,
• happy,
• cataclysmic,
• exogenous,
• unavoidable,
• extreme,
• stressful,
• accidental,
• relevant,
• hazardous,
• acoustic,
• organizational,
• traumatic,
• dramatic,
• adverse,
• unpleasant,
• costly,
• corporeal,
• musical,
• localised,
• harmful,
• environmental,
• astronomical,
• violent,
• deadly,
• untoward,
• specified,
• exceptional,
• unwanted,
• external,
• unique,
• temporary,
• positive,
• geographical,
• internal,

Simple categories matching spontaneous:

• occurrence,
• action,
• event,
• resistance,
• mutation,
• movement,
• behavior,
• change,
• form,
• activity,
• emotion,
• speech,
• expression,
• experience,
• use,
• reaction,
• violence,
• animation,