a.
1.
Bold, daring, courageous, venturesome, adventuresome, adventureful, venturous, chivalrous, doughty, enterprising.
2.
Rash, reckless, precipitate, headlong, foolhardy, full of hazard.
3.
Hazardous, dangerous, exposed to dangen perilous, full of peril, uncertain, full of risk.