The term "weak hands" typically refers to an investor or trader who is driven by fear to quickly exit positions on almost any news or event that they consider detrimental, resulting in realized losses and suboptimal returns on investment (ROI). They tend to adhere to a set of rules that makes their trading activities predictable and are easily "shaken out" by normal market price gyrations. The net result is that they end up buying at the highs and selling at the lows, a surefire way to lose money.