His naive approach to investing led to significant losses.

naive 是形容词，来自法语，意思是"天真的、幼稚的"，指缺乏经验或判断力，容易轻信他人或简单看待复杂问题。在金融投资领域，naive approach 特指不考虑市场复杂性的简单投资策略。