1) A ninjette is considered to be a small ninja, or in some cases a midget.
2) Sometimes ignorant people like to call themselves ninjettes to make themselves sound more awesome.
Person 1 "Man did you see that ninjette pay for his burger?
Person 2 "Yeah, they scare the shit out of me."
Miranda-Blah Blah Blah My names Miranda and i think im an awesome ninjette!
Billy-Miranda, your full of crap and not the least bit intimadating.
Miranda-Shut Up Billy! I'm gonna take you lunch money!