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.

(chiefly UK, history) A three-wheeled motor vehicle allowing disabled people to drive on the road, no longer used because of safety concerns.

plural of invalid carriage

plural of invalid chair

(dated) An early wheelchair.

To leave or be excluded because of an injury or infirmity

simple past tense and past participle of invalid out

The theater; stage productions generally.