def.1: a person whos constintly on you about everything in terms on ur sack meaning on ur back in a annoying way.

Def. 2: a male or female who has sex with more then 1 person. in terms having sex with different people on different days
ex.1: yo hope of my sack man.. you sack jumper

ex.2: i heard your girls a sack jumper.. shes sleep with everyone in town.
by rbskillz February 14, 2011
Get the sack jumper mug.