Baffle
WordNet
noun
(1) A flat plate that controls or directs the flow of fluid or energy
verb
(2) Check the emission of (sound)
(3) Be a mystery or bewildering to
"This beats me!"
"Got me--I don't know the answer!"
"A vexing problem"
"This question really stuck me"
(4) Hinder or prevent (the efforts, plans, or desires) of
"What ultimately frustrated every challenger was Ruth's amazing September surge"
"Foil your opponent"