The Navajo tried to copyright the word Navajo in the mid 70's but the court did not let them because the word was too common.
The only way to get into legal trouble is via the Indian Arts and Crafts Act which says you cannon claim something is 'Indian made', which Navajocoin is not. no one has or is claiming that this coin was made by the Navajo Nation.
There is no legal problem here.
Thanks Coindeath for giving insight into this matter.
I'm glad to see folks beginning to reply to my comment in some way other than GTFO, which seemed to be the only voice earlier. I would only add to CoinDeath's comment that while something may be legally fine, ethics may add another layer to this. Consider that if Navajo nation attempted to copyright their name and were rejected by a US court what that implies about how they might feel about someone using the name without their permission. Perhaps the court will be on the side of the person using the name, but again I might ask: how can you say you are honoring someone if you are explicitly going against their wishes (ie, using a name they have tried to copyright without their permission).
Please also understand I have no holdings in altcoins, I have no hidden motivation to spread FUD about your project. I merely am trying to highlight that if you really want to honor Navajos, I believe you should make a serious effort to try to find out what Navajo people opinons are. I also received a message from lab rat, it was respectful and I hope he can contribute to this topic?
Thanks again to those who have responded with real, constructive comments rather than the embarrassing GTFO that I heard from others in this thread.