no skin offone'snose字面意思是「不會從我鼻子上掉皮」，實則是指「對某件事不在乎，不會受到損害，跟某人無關」。所以It's no skin off my nose.應該理解為：那不關我的事。no skin off one's nose英語解釋為of no interest or concern sb to沒有興趣或不關心。
看看老外聊天時怎麼用這個詞組：
A:Since the matter has already happened，why don't you help him find any solutions？
既然問題都已經發生了，為什麼你不幫他想想辦法呢？
B:It's no skin off my nose.He is bringing trouble upon himself.
這跟我無關。他這是在自找麻煩。
你還可以用以下語句表達「在乎」或「不在乎」：
1、It's not my business.=It's none of my business.
這不關我的事。
2、It has nothing to do with me.
這與我無關。
3、I couldn't care less.=I don't care at all.=I don't give a hoot.
我不在乎。
care/give a hoot介意；在乎
4、I don't care a fuck！
我一點兒都不在乎！
not care/give a fuck毫不在乎
5、I don't give a damn！
not care/give a damn毫不在乎
6、I couldn't care more.=I care a lot.=I care deeply.
我很在乎。
7、It is my business rather than yours.
這是我的事，與你無關。
8、What he has done is no business of mine.
他所做的事與我毫不相干。