outbreak - n. the sudden arrival of disease or war

index - n. a group of things that are listed together

confidence - n. certainty that things will go well

contagion - n. in economics, the process of one bank or company failure after another

inevitable - adj. something that is almost certain to happen

bankrupt - adj. not having enough money to pay debts

volatility - n. changing in sudden or extreme ways

frequency - n. the condition of something happening often