invalid

Short definition from Wiktionary

Adjective

1. 1
   Not valid; not true, correct, acceptable or appropriate.
2. 2
   Suffering from disability or illness.
3. 3
   Intended for use by an invalid.

Noun

1. 1
   Any person with a disability or illness.
2. 2
   A person who is confined to home or bed because of illness, disability or injury; one who is too sick or weak to care for themselves.
3. 3
   A disabled member of the armed forces; one unfit for active duty due to injury.

Verb

1. 1
   To exempt from (often military) duty because of injury or ill health.
2. 2
   To make invalid or affect with disease.