Meaningless Questions are often paradoxical and are simply tricks used to paint an opponent into a corner. They have no merit and do not contribute to an honest debate.
Example: "What happens when an irresistible force meets an immovable object?"
(If one of these exists, the other cannot.)
(Adapted from: http://www.brainpickings.org/index.php/2014/01/03/baloney-detection-kit-carl-sagan/)
Example: "Can God microwave a burrito that is too hot for Him to eat?" or "Can God create a rock that is too heavy for Him to lift?
(This is simply paradoxical trickery.)
Example: "How far is up?"
("Up" is not a measurable entity; the question is lame because one should not ask someone to measure something that everyone knows cannot be measured.)
(Adapted from: http://www.nobeliefs.com/fallacies.htm)