形容词

1. 轻浮的;轻佻的;草率的
If you describe someone as frivolous, you mean they behave in a silly or light-hearted way, rather than being serious and sensible.

2. 无聊的;无用的;浪费的
If you describe an activity as frivolous, you disapprove of it because it is not useful and wastes time or money.

1. not serious in content or attitude or behavior

e.g. a frivolous novel
a frivolous remark
a frivolous young woman