I stopped telling people Ninjutsu quite a while ago. Now, if people find out that I practice anything at all and if they ask, I'll just say "Taijutsu". Sometimes they ask if that's anything like Taichi and depending on whether I want to explain anything or not, I'll answer "yeah, sort of..." and hope they're satisfied. Then if they pry even more, I just say it's a lot like Jujutsu but has some Karate mixed into it and that does the trick most of the time.
Telling people that you practice Ninjutsu gets you all sorts of odd looks and bad jokes...
Interesting that you use 'Taijutsu'. I honestly would have thought that would lead to more questions or blank expressions. I've been trying a new thing recently where I just say Japanese mixed martial arts minus the sport and that seems to work. People nod wisely and walk off
I just say "jujutsu and kendo", pronouncing it "jujitsu", since that's the way most people say it. If they're actually "in the know" and know the differences between kendo, kenjutsu, judo, jujutsu, BJJ, karate, sumo and kempo, then I'll tell them more about koryu kenjutsu, Japanese jujutsu, and how some of our schools use koppo, koshijutsu, taijutsu and ninpo. I try to avoid the N word unless they already know something about the Genbukan, the Bujinkan, etc.
It seems like a lot of people try to avoid saying "Ninjutsu" when they are asked what they do. Very ninja like! My thing is that if I have to answer that question about what martial art I study at all then I start thinking I'm not very good in the arts I'm studying. Occasionally though, if I think someone might be sincerely interested, I will go into a little more detail about koppojutsu, koshijutsu, kenjutsu, ninjutsu, 9 ryu, etc.
I have no problem telling people I study Ninpo. I've never had a sneer or any kind of verbal jab from anyone. The people I work with have asked what it is, and I usually answer that with a couple of videos of Tanemura Soke.
I personally just let the people I know and trust know that information. You know, the people that when quizzed by LEOs (good term that one!), won't usually be the ones who say "Oh he trains in X". At least I think so. I've been lucky not to have needed any of my (very little) amount of training to diffuse or disarm a situation, though verbal diffusion's a good one.