sophism (n.)

early 15c., earlier sophime (mid-14c.), "specious but fallacious argument devised for purposes of deceit or to exercise one's ingenuity," from Old French sophime "a fallacy, false argument" (Modern French sophisme), from Latin sophisma, from Greek sophisma "clever device, skillful act, stage-trick," from stem of sophizesthai "become wise" (see sophist).