What is the meaning of "out of curiosity" [closed]

What is the meaning of "out of curiosity"?

Could it mean out of ideas? Or maybe it means he is curious? How should I know what he means?

out of curiosity simply means that you are interested in knowing something for no other reason except that you just want to know it. Does that make sense to you? I think a couple of examples would help here.

Example #1:

— I know it's none of my business, but just out of sheer curiosity how much money does he make a month?
— I think, something like five grand.

Example #2:

— I know it's not very appropriate to ask a woman this, but just out of curiosity, how old are you?
— I'm 32.

out of something means that you are doing something only for that reason you. So, you could say, for example:

— Why didn't you call the police the moment it happened?
— Out of fear. I was afraid that I would get arrested.

What this says is that the reason that you did not call the police was fear. In other words, the reason you did not call the police was that you were afraid they would arrest you too.

I hope everything is clear now.