Modifiers matching setback:

• physical,
• major,
• minor,
• unforeseen,
• financial,
• serious,
• unanticipated,
• unforeseeable,
• unexpected,
• economic,
• notable,
• personal,
• temporary,
• sudden,
• national,
• social,
• immediate,
• emotional,

Simple categories matching unforeseeable:

• change,
• risk,
• event,
• situation,
• calamity,
• disturbance,
• disaster,
• condition,
• contingency,
• reason,
• inactivity,
• setback,
• occurrence,
• circumstances,
• incident,
• thing,
• circumstance,
• catastrophe,
• cause,
• development,