A jiggaboo is person that reinforces the many black stereotypes such as...
Mainly listens to rap music (i.e. 2-Pac)
Eats chicken all the time (i.e. KFC)
Uses common black phrases or words (i.e "What it do?" and "folks")
Wears name brand clothes (i.e. Rocawear or Ecko)
Lazy and stupid
Smokes alot of weed
Leeroy and Dominique, both jiggaboo examples, share a conversation as they eat cheetos while looking at thier myspace...
Leeroy: "Hey Dominique, take a look at my baby's momma, Taykisha."
Dominique: "Damn folks, dat gurl gots a thick ass booty. No wonder you be chillin' at hurr crib awla time."