Combination of Keif and reefer. Used among well informed potheads to refer to dank that gets its power from the the crystals/orange hairs/and fine resin particles (keif)that come off a kind bud. When smoked a very very intense high will ensue.
Not to be confused with Keith, which is a really fat joint, though the term probably originated from people somehow misusing Keith for Keif.
If a street nigger pulled his malt liquor bottle away from his bumper lips and broke it on one of those nigger benches and then stabbed some caucasian people, that would be a good example of someone being nigger knifed.
A verb most commonly heard in online FPS (First-Person Shooters.) It is the act of stabbing another player or person with a knife and thus killing them instantly.