Meaning:

“扫” means “to sweep,” and “楼” refers to “building.” This term, coined by Chinese people, refers to the scenario where salespeople go from door to door to sell insurance or enlist new credit card users. Later on, people use it to describe a similar behavior in jobseekers who send copies of their resumes aimlessly to any firm they can find through phone numbers and addresses from yellow pages or other means.

Example:

A: 刚刚谁敲门？

Gānggāng shuí qiāomén？

Who was at the door?

B: 一个扫楼的保险推销员。

Yīge sǎolóu de bǎoxiǎn tuīxiāoyuán。

A door-to-door insurance salesman.

A: 那你怎么还跟他聊半天？

Nà nǐ zěnme hái gēn tā liáo bàntiān？

Then why did it take you so long?

B: 我看他挺可怜，不忍心直接把门关上。

Wǒ kàn tā tǐng kělián，bù rěnxīn zhíjiē bǎ mén guānshang。

The guy looked pitiful, and I just didn’t have the heart to shut the door on him.