confound

(verb) be confusing or perplexing to; cause to be unable to think clearly. Synonyms: confuse, throw, fox, befuddle, fuddle, bedevil, discombobulate. Examples: "These questions confuse even the experts." "This question completely threw me." "This question befuddled even the teacher."

(verb) mistake one thing for another. Synonyms: confuse. Examples: "You are confusing me with the other candidate." "I mistook her for the secretary."