Push dagger is a weapon where you hold it in your fist and can do punching and slashing attack with it. It's like brass knuckles only with blades.
The push dagger is considered highly dangerous, and its possession has been banned in many U.S. states, as well as Canada, Australia, United Kingdom, and New Zealand (Note that possession is only illegal if the blade is carried or wielded in public) =.= duhh
A cool website on how to use push dagger. Visit it, you will not regret ^^.