I don't give a shit.

不屑一顧。

Same as "I don't give a damn.". It is not polite to use "shit" normally.

Shit 跟 damn 都是最不值錢的東西， 連 shit 跟 damn 都不給，就是說根本不屑一顧. 比如說你知道有人在背後說你壞話， 你就可以這麼說， I don't give a shit.