Definition
A question that attempts to elicit an answer in a certain way, usually incorrectly (i.e. that seems to have an obvious answer that is however incorrect), or a question that does not have a correct answer or that hides the real question or some difficulty.
How People Actually Use It
An inquiry having no correct answer, or one asked for the sole purpose of starting controversy or eliciting certain responses. Basically, a no-win situation.
"Girlfriend asks: do I look fat in this? (trick question) If you tell her she does, she'll throw a fit and tell you how insensitive you are. If you tell her she doesn't she'll call you a liar and go off on a tangent about how "all men are the same" or some nonsense like that"
Source: Urban Dictionary