"Big," "boring," "purple," "quick" and "obvious" are all adjectives.

adjectives 是形容词 adjective 的复数形式。adjective 来自拉丁语 ad-（表示"添加"）和 ject（"投掷"）的组合，字面意思是"被添加的东西"，在语法中指用来修饰名词或代词的词类，表示事物的性质、状态或特征。