Word：sǐ dìng le 死定了 (for emphasis: place stress on the dìng!)

Meaning: to be done for; screwed, dead meat… etc…

Use:

1.) kǎoshì qián wǒmen yào hǎo hǎo xúe xí, yàobù kǎoshì de shíhòu wǒmen dōu sǐdìng le.

    考试前我们要好好学习，要不考试的时候我们都死定了。

     We need to study hard before the test, or else we'll be dead meat.

2.) wǒ de tóngxúe zúotiān wàng le zùo zùoyè! tā jīntiān shàngkè sǐdìng le!

    我的同学昨天忘了做作业！他今天上课死定了！

    My clbummate forgot to do his homework, he'll be “done for” today in clbum.

Similar word: wán dàn le 完蛋了=finished-screwed-….this is a great one.