Usually would refer to a darker-skinned, heavy-set black woman.... The kind you might see in Wal-Mart waddling down the aisles. Gapped, or missing teeth...real big lips...living on welfare...loud demeanor...thick ebonic accent are all common traits of the Jiggabroad.
Alphamatical equation:
Jiggaboo+Broad=Jiggabroad.
As two white guys are walking through Wal-Mart, one says to the other: "Hey Frank, did you just see that jiggabroad stuff that ham under her dress??"