① Not necessary
没必要

It's not necessary to wear a tie.
没必要系领带。

斩钉截铁表达“不系领带”：
You shouldn't wear a tie.
你不应该系领带。

Don't wear a tie.
不要系领带。

② Uncalled-for
不必要的，不适当的

What I just said was Uncalled-for.
我刚才说那些是不适当的。

Some of his comments are a bit uncalled-for.
他的有些评论是不适当的。

③ No need
不用，不需要

There's no need for any ID.
这里不需要出示身份证件。

No need to thank me. It was my pleasure.
不用感谢我。这是我的荣幸。

④ Unwarranted
不必要的

Your actions were unwarranted. He didn't deserve it.
你那样做是不必要的。 他不应得那样的下场。

Her remarks were unwarranted. I didn't say anything about her.
她的言辞是不必要的。我没说关于她的任何事情。

⑤ Not/nothing important
不重要，不必要

It's not important. You don't have to do that.
那个不重要。你不用那样做。

It's nothing important. Just forget it.
那个不重要。当我没说。

Just forget about it.
当我没说。