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.

plural of invalidator

One who, or that which, makes invalid.

(UK) The act of exempting someone from duty because of injury or ill health.

present participle of invalid

plural of invaliding

plural of invalidity

plural of invalidism