Not valid; not true, correct, acceptable or appropriate.

(dated, sometimes offensive) Any person with a disability or illness.

Suffering from disability or illness. / Intended for use by an invalid.

(Britain, transitive) To exempt from (often military) duty because of injury or ill health. / (transitive) To make invalid or affect with disease.

The act of invalidating, or the state of being invalidated

To make invalid. Especially applied to contract law. / To make or declare (an argument, statement, or theory) unsound or erroneous; disprove.

The condition of an invalid; sickness; infirmity.

The state of being invalid; lack of validity.

Third-person singular simple present indicative form of invalidate

present participle of invalidate