na-adjective
adventurous; risky
Describes a person, plan, or action that involves risk or a willingness to take chances. Often used for ventures, investments, or bold ideas.
彼は冒険的な投資を好む。
He likes adventurous investments.
その計画は少し冒険的すぎると思う。
I think that plan is a little too risky.
危険 is a noun/adjectival noun meaning 'danger' or 'dangerous', focusing on the presence of danger rather than the spirit of adventure.
Compound of 冒険 (adventure) + 的 (-like, -ish). The suffix 的 is a productive way to form adjectival nouns from nouns.