A word of acknowledgement and/or slang commonly used by Native Americans. Definition can change depending on the conversation. It can be used in place of other words/phrases such as "right", no problem, you're welcome, don't worry about it, etc. The g is silent, pronounced "nuh".
Guy: Hey, how's it going? Nice weather we're havin.
Native: Gnuh, I was just trying to buy some liquor to drink cuz it feels good to lay down in da sun.
Guy:Ya, I know what you mean.
Native: Ya, man. Think you could get some brew?
Native: Alright! Thanks, man.