random

n. 随意,任意
a. 任意的,随便的,胡乱的

The librarian took a book at random from the shelf.

图书管理员从书架上随便拿了一本书。

Marked by a lack of care, accuracy, or organization; random.

漫无目的的缺乏谨慎、精确或组织性的；随意的