Did you want to say "Koitsu no namae wa nan da" ? If so, we write in japanese こいつの名前は何だ。 Meaning:　What's his/her name?　(for me, it's more like: What's the name of this person.) And the situation you can use this sentense is when you are asking someone to tell you the name of someone(who is not the one you are asking the question to) near you. So, you must have at least 3 people(including you) at the place. I also recommend you not to use this sentense as it's very impolite to talk to people like this in Japanese.... Anyway, hope it helped you a bit.

ok there is a typo, anyway not polite.

What you have written means nothing. There's a mistake somewhere.