Since it hasn't been done in a while

Q- 'Quakes (which happen frequently in Japan. Ninja would create illusions of earthquakes to confuse and frighten their foes.)

Edit: Damnit! Beaten to the punch. Mine is better, though =P.

R- Razor sharp blades


T- Throwing ninja stars

Uber because ninjas are.

V- Very ((insert ninja term here))

Wicked (cool).

X-rays! because ninjas get their bones broken a lot!

Y- You’re dead if they visit you

Such a cop out. One word please!

Z - Zoom! There goes the ninja!

I vote on this one as the funniest.

Oh ho ho. We’ll I’m spent.

For a better version of Y:
Yuri/Yaoi: There are gay ninja.

There’s a term for gay ninjas?

Yaoi = guy-on-guy
Yuri = girl-on-girl.

Bininja would do.

BTW, the female form of ninja is kunoichi. Means something like “they (men) die dry” (I think).

Actually, they were also called ninja-ko, after Joe Lieberman invaded Japan with political correctness, in the mid-ninth-century.
Actually, they were called that is their importance grew equal with the other ninja, so they were called ‘ninja-girl.’ Which is kinda weird, since it means more ‘little girl,’ but that’s okay.

A - awesome

B - BAMF! (the sound of a ninja vanish.)