audacity

n.
1. 大胆,无畏[U]
Sky-diving takes both audacity and skill.
特技跳伞需要胆量和技巧。
2. 鲁莽;胆大妄为,厚颜无耻[U]
He had the audacity to ask for an increase in salary.
他竟然厚着脸皮要求增加薪水。
3. 鲁莽行为;放肆的话[P]