Adjective

1. Containing an error; inaccurate.
   • His answer to the sum was erroneous
2. Derived from an error.
   • His conclusion was erroneous as it was based on a false assumption
3. Mistaken.
   • His choice at the line-up was erroneous as he had only seen the mugger for an instant
4. signifies a deviation from the requirements of the law, but does not connote a lack of legal authority, and is thus distinguished from illegal.
   • If, while having the power to act, one commits error in the exercise of that power, he acts erroneously.