It is a combination of the words slut
. A sleg is a woman who decides it is a good idea to get knocked up as much as possible. She basically use her eggs to get on the Maury show and go through as many guys until she finds her child support check. They continue to do this until they have several children. A slegg usually has a very low iq and no other talents besides being able to bear children and maybe give a good blowjob.
Britney is such a slegg, shes had 7 babies with 5 different men and is married to Juan who works at the 7-11.