Player(s) and possibly NPCs can somehow throw people upwards, usually as part of a series of chained attack. Commonly accomplished by swinging a weapon upwards, an uppercut or literal throw.
Alternate names: Fling up, Launcher
Name variations: toss up, throw up
The first video game about Knock up was released on June 2005.
Commonly part of a combo attack, knock up, and follow up combo attack chain, variously either with the character jumping in the air with the target and continuing to slash them up there, shooting them while in the air, grabbing them (possibly with a [grappling] hook and tossing them at the ground), waiting for them to fall back low enough before doing some special move that's only possible on targets in air, and so forth.