A person who stalls the discourse of your lecture/seminar/class by asking an unnecessary or badly thought out question, the question being irrelevant, ignorant or just no-one gives a shit.
Prof: "If we fill this shape with small rectangles - "
QW: "Surely! you should use triangles?"
Prof: "Honestly it makes no difference"
Student (aside): "Seriously, who's that Question Wanker?"
Prof: "And that is morality according to Kant"
QW: "Didn't Bentham think morality was completely different?"
Prof: "Yes, but we're talking about Kant"
Student: "You're such a question wanker"
Teacher: "Condoms should be changed after half an hour of use"
QW (also blonde): "My boyfreind lasts only 10 minutes, does that mean we can use it 4 times"