overfly

The opposite of "understand":
under -> over
stand -> fly
Basically meaning "don't understand".

Person 1: "Aaaaand that's how quantum mechanics work!"
Person 2: "...I overfly what you mean"

John Watson: "I believe the killer's motivations are quite understandable, Holmes."
Sherlock Holmes: "On the contrary, my dear Watson. Their motivations are quite overfliable..."