a + lost + cause = a lost cause ( what !!! )

I played with my sister, however it was a lost cause



Hi everyone ... !
I am interested in learning idioms with more details such as etymology. like in Arabic language we have such idioms that have stories or reasons behind them. I would like to discuss "a  lost cause"  idiom.
According to Speak English Like an American, this idiom means something hopeless. Moreover,  I find that meaning in another website with synonyms ! ( excited face )   

Also, according to the oxford English dictionary " lost cause" mentions as:

As we can see clearly that there are many usages for this idiom for many years. You can find a good meaning for many idioms ad one of them " a lost cause"

http://esl-bits.net/idioms/id22.htm

I search in Google to see how it work, and I find this: 

" Baby you're lost
Baby you're lost
Baby you're a lost cause

There's too many people you used to know
They see you coming they see you go
They know your secrets and you know theirs
This town is crazy; nobody cares "

Have a great day !

Raedah Alyousif