twinjas
A ninja who has a twin, who also happens to be a ninja. It is a portmanteau of "twin ninjas".
Kyo and Kai are the most deadly twinjas anyone has ever encountered.
twinja
Kawasaki's line of twin-cylinder Ninja motorcycles (the EX- line), including the Ninja 250, 500 and 650; this is distinct from their four-cylinder supersport cousins (the ZX- bikes).
No, it's not a race bike, it's a Twinja.
twinja
2 ninjas
look is a ninja, and there is two of them... so is a twinja