to make a person unable to move by tying a rope or something similar around their body or part of their body

The burglars had tied him up (to the bed). 窃贼们把他捆了起来（绑在床上）。

When someone is tied up, they are busy or prevented from doing something, such as speaking to someone or going somewhere, because of being involved in another event or activity.

I'm afraid we can't meet till Wednesday - I'm tied up on Monday and Tuesday. 恐怕我们要到周三才能碰头——我周一和周二都脱不开身。

Mrs Moran is tied up in a meeting at the moment, but I'll ask her to call you later. 莫兰夫人现在正开会脱不开身，我会告诉她稍后给你打电话。

to fasten something together using string, rope, or something similar

It was an old-fashioned parcel, tied up with string. 这是一个老式的包裹，用细线绑着。

to cause something, often money or possessions, not to be available for use

All my money is tied up in property. 我所有的资金都投在房地产上了，无法动用。

He tied up the printer all morning, printing out copies of his presentation. 他整个早上一直占着打印机打印他的报告。