Jump-Up is a subgenre of jungle and drum and bass that was popular with fans of drum and bass in the mid 1990s and was designed to be played in mainstream nightclubs to get a crowd to "jump up" and dance.
Most frequently in modern Jump-Up, an element of highly energetic "rave stabs" are often heard. While some critics dismissively conclude that this subgenre of drum and bass is more accessible to casual listeners with the disposable fanbase mostly consisting of young ravers that listen to the subgenre for anywhere between 2-3 years, Jump up is actually more closely related to the more popular 1996-1997 era of jungle-drum and bass, known for its 'warmth' through notable beat and melody syncopation and cleaner, simpler sounding heavy basslines (as opposed to the lighter weight, more distorted basslines of the colder, more precise sounding techier styles of Neurofunk & Techstep coming out around this time).
Older examples include DJ Zinc's Super Sharp Shooter or his remix of the Fugees' Ready Or Not (known at the time as Fugees or Not), which also samples Redman on the original version of his first collaboration with Method Man, How High. Extensive use of hiphop samples was common in jump-up in the late 90's.
Additionally Jump Up is a clean beat not similar to the popular amen and apache drum loops. Jump up is easy to distinguish from its other jungle and future DnB styles due to its simplicity, 3 tier basslines (high, mid, low) that provide the thick and clean baselines so commonly associated with Jump Up, and Simple KickXXXSnareXXXXXKickXSnareXX Pattern. Drum rolls are often long and composed mostly of kicks and often have some effect like flange thrown over them.
On a social level within the Drum N Bass community Jump Up is often looked down upon as a lighter and more mainstream (which it is) version of the more complex Drum N Bass Genres.