Gaosoul Forever translated it as Wind ninja I think, and from Supersentai.com
Ninpuu means some sort of Ninja Technique. "Shinfuu" is "Divine Wind" aka "Kamikaze"... Most ninja techniques (ninpouu) retain their Japanese spelling in English, since it is a recognized martial art outside of Japan. I mean, we say "ninja" not "stealth people" or "assassins"... right? Our "Hurricane" comes from the Japanese "Hariken"