Cut-Up/DJ tags on Discogs refer to recordings that were released as DJ Mixes, such as mixtapes or compilation CD's/records that were mixed by a DJ. It can also refer to recordings of turntablism or otherwise recordings where the DJ is taking an active role of cutting up, mixing and blending songs.
Cut-Up DJ is also often used in reference to DJ Battle tool records, which are usually soundbytes and breaks that are used by battle DJ's in direct competition.
See also: Turntablism and DJ Battle Tool