Great tool primarily used for cutting flesh and plant tissue. It's use has gone down since the invention of the gun.

Intelligence agency term for "psychological operation". A government or corporate-sponsored operation, usually taking the form of a "terrorist attack" or "crazed gunman on a spree", with the intent of panicking the public into demanding more police and laws inhibiting freedom. Psyops are usually carried out by drugging a civilian or group of civilians with aggression-promoting drugs, psyching them up, arming them, and sending them out to commit mayhem. Government-sponsored terrorism. See also blackshirts, conspiracy

1) An object with a blade, primarily used for cutting.

2) To stab someone with a knife.

A Small Sharp blade that is used for cutting things. Can change the tide of battle.

To knife somebody is when a mans penis gets shoved like a knife into somebody vagina.

a knife can come in many shapes and sizes.
usually consist of a blade made of some kind of metal or stone, with a handle at the other end.
there are fixed blade knives. (meaning that they don't fold, they need a sheath to keep from getting cut)
and folding (the blade usually folds into the blade.)
one of the most widely known is the switch blade. (just a knife that has a spring loaded blade, no big deal)
and then there are knifes that have the blade the slides out of the handle. and some that have handles that fold onto the blade.
then there are piece of crap fantasise knives, dont waste your money.
not a weapon unless used as one, a knife is a tool, that doubles as a weapon.

then there is the term, to knife.
means to stab or cut someone, but not necessarily kill them.
very similar to shanking someone. (although shanks are better at a stab, usually favored in the hammer fist or oriental knife hold.)

A sharp object used for killing people who don't do as they're told.