1) A jerk, or an event/situation that is influenced by a jerk which causes something shitty to happen to another person; usually to an innocent bystander
2) Suffering the consequences of someone else's stupidity
3) To be splattered by semen; often furtively expelled by a stranger in public, or to a person passed out at a party
Bill: "Oh man - is this jizz on my jacket? I just walked to the corner store and back. I feel like a dirty Lady Macbeth."
Tim: "Damn. That sucks, buddy. Could it be from that apartment building you just passed? You were totally a victim of jerkumstance."