I´ve seen the word ´napcan´ a few times on this site and each time it has been translated to English in a different way:

what can we do about it

why do you want to ...

what will you do with ...

Can someone please explain the possible meanings of ´napcan´ and which words, if any, it is derived from.

Thanks

napcan is non-standard form of Ne yapacaksın ? which normally means "What are you going to do?"

In spoken Turkish napçan / naaapcan / naapçan means

1) What will you do ? / What are you going to do ?

2) Why do you ask ?

For example :

Nereye gidiyorsun ? = Where are you going ?

Answer : Naapcan ? = Why ? Why do you ask ? Why do you care where I am going ? What´s it to you ?

It can be okay or rude depending on your tone of voice.

Merhabaturkish.com

Thanks Jaydee that explains it very well.