Thayer's Greek Lexicon

 1. a wandering, a straying about
  1) one led astray from the right way, roams hither and thither
2. metaph.
  1) mental straying
2a1. error, wrong opinion relative to morals or religion
  2) error which shows itself in action, a wrong mode of acting
  3) error, that which leads into error, deceit or fraud