Containing an error; inaccurate.
His answer to the sum was erroneous.
Derived from an error.
His conclusion was erroneous, since it was based on a false assumption.
Mistaken.
Her choice at the line-up proved to be erroneous, as she had only seen the mugger for an instant.
Wandering; erratic.
Deviating from the requirements of the law, but without a lack of legal authority, thus not illegal.