overconfidence (n.)

• arrogance
• assurance
• assuredness
• belief
• brashness
• brass
• certitude
• cheek
• chutzpah
• cocksureness
• confidence
• conviction
• courage
• faith
• gall
• heroics
• hubris
• improvidence
• imprudence
• impudence
• indiscretion
• injudiciousness
• insolence
• poise
• pomposity
• positiveness
• pride
• rashness
• security
• self-assurance
• self-confidence
• self-importance
• self-reliance
• sureness
• surety
• temerity
• trust
• unwariness