Modifiers matching circumstance:

• unfortunate,
• unforeseen,
• historical,
• unavoidable,
• stressful,
• common,
• catastrophic,
• unforeseeable,
• exceptional,
• external,
• extreme,
• negative,
• threatening,
• extraordinary,
• unexpected,
• verifiable,
• relevant,
• unusual,
• severe,
• exigent,
• special,
• unique,
• individual,
• bad,
• personal,
• involuntary,

Simple categories matching unavoidable:

• activity,
• mishap,
• event,
• danger,
• situation,
• matter,
• hardship,
• incident,
• death,
• phenomenon,
• cause,
• condition,
• conflict,
• occurrence,
• error,
• force,
• injury,
• contingency,
• predator,
• circumstances,
• reason,
• impurity,
• hazard,
• catastrophe,
• problem,
• circumstance,