er·ro·ne·ous (ĭ-rō'nē-əs) adj. Containing or derived from error; mistaken: erroneous conclusions.
[Middle English, from Latin errōneus, from errō, errōn-, a vagabond, from errāre, to err, wander; see ers- in Indo-European roots.] er·ro'ne·ous·ly adv., er·ro'ne·ous·ness n.