temerity

Use the noun temerity to mean the quality of being unafraid of danger or punishment. If you have the temerity to jump off the bridge even after hearing about the risk of instant death, you truly are a nutcase.

Someone who has the temerity to do something is usually considered to be bold in a foolish way. Near synonyms are audacity and recklessness. Temerity is from Middle English temeryte, from Latin temeritas, from temere "by chance, rashly."