One who is composed of the fluids the penis secretes while acting like an utter idiot, therefore being referred to as a "retard." Widely and mainly used as an insult, this word can be endearing if used by the right person.
Sarah- "God damn it! My boyfriend juz broke up with me!"
Kate- "Fuck that jiztard! He didn't deserve you. You can do better than that."
Sarah- "Yeah, les' go to dah club and get hyphy up in dat bitch!"
Girl- "Baby, do you wana smash?"
Boy- "You know you don't have to ask you, jiztard."
Girl- "Mmmm, I love you."