It means "which one" or "what" depending on the context.
Here are some examples:
* Ndeipi imbwa yako? (Which one is your dog?)
* Ndeipi iwe unoda? (What do you want?)
* Ndeipi chikonzero chako? (What is your reason?)
It's important to note that "ndeipi" is often used in questions, and its exact meaning can vary depending on the surrounding words and the context of the conversation.