temerity (n.)

• assurance
• audacity
• brashness
• brass
• cheek
• chutzpah
• daring
• foolhardiness
• gall
• hardihood
• hardiness
• heedlessness
• heroics
• hubris
• impertinence
• impetuosity
• improvidence
• imprudence
• impudence
• indiscretion
• injudiciousness
• insolence
• intrusiveness
• nerve
• overconfidence
• precipitateness
• rashness
• recklessness
• unwariness
• venturesomeness