General Antonyms:
* Famine: This is the most direct opposite, meaning a severe shortage.
* Scarcity: A lack of something.
* Drought: A prolonged period of dryness, often implying a lack of resources.
* Depletion: The act of using up or exhausting something.
* Crisis: A time of great difficulty or danger.
More Specific Antonyms (depending on the context):
* Bust: A complete failure, often in business or mining.
* Flop: A complete failure, especially in entertainment or business.
* Disaster: A sudden event causing great damage or loss.
* Setback: A temporary delay or difficulty.
* Loss: The state of no longer having something.
The best antonym will depend on the specific context in which you are using the word "bonanza."