Derived from an error.
Mistaken.
Containing an error; inaccurate.
Deviating from the requirements of the law, but without a lack of legal authority, thus not illegal.
Intended for use by an invalid.
Not valid; not true, correct, acceptable or appropriate.
Suffering from disability or illness.
To make invalid or affect with disease.
To exempt from (often military) duty because of injury or ill health.