foolish 是一个形容词，主要意思包括：

1. 愚蠢的，缺乏判断力的（如：He made a foolish mistake.）

2. 鲁莽的，轻率的（如：She acted foolishly by jumping into the river.）

3. 荒谬可笑的（如：The plan was foolish and never worked out.）

1. It was foolish of him to ignore the warning signs.

（忽视警告标志真是愚蠢的。）

2. The company's decision was foolish and led to a financial disaster.

（公司的决定很愚蠢，导致了经济灾难。）

3. His foolish behavior embarrassed everyone at the meeting.

（他鲁莽的行为让在场的每个人都感到尴尬。）

该词带有明显的主观评价色彩，通常用于描述缺乏常识或判断力的行为。