[ in-vuh-lid ]
See synonyms for invalid on
  1. an infirm or sickly person.

  2. a person who is too sick or weak to take care of their own needs: My father was an invalid the last ten years of his life.

  1. Archaic. a member of the armed forces disabled for active service.

  1. unable to care for oneself due to infirmity or disability: his invalid sister.

  2. of or for invalids: invalid diets.

  1. (of things) in poor or weakened condition: the invalid state of his rocking chair.

verb (used with object)
  1. to affect with disease; make an invalid: He was invalided for life.

  2. to remove from or classify as not able to perform active service, as an invalid.

  1. British. to remove or evacuate (military personnel) from an active theater of operations because of injury or illness.

verb (used without object)Archaic.
  1. to become an invalid.

Origin of invalid

First recorded in 1635–45; from French invalide, from Latin invalidus “weak, feeble, infirm”; See in-3, valid

Words Nearby invalid

Other definitions for invalid (2 of 2)

[ in-val-id ]

  1. not valid; not founded in truth, fact, or logic, and hence weak and indefensible; unsound; untenable:The entire argument depends on an invalid assumption.

  2. deficient in effectiveness; inadequate:Self-perception is an invalid method of judging one's own biases.

  1. void or without legal force, as a contract:Without the grandfather clause, thousands of such warranties would now be invalid. The coupon is invalid in our state.

  2. not accepted or permitted because a required element or the necessary form is lacking; not usable:Anything with fewer than five characters is an invalid password, and you’ll get an error message prompting you to pick something more secure.

Origin of invalid

First recorded in 1630–40; from Latin invalidus “weak, feeble”; see invalid1

Other words for invalid

Other words from invalid

  • in·val·id·ly, adverb
  • in·val·id·ness, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use invalid in a sentence

British Dictionary definitions for invalid (1 of 2)


/ (ˈɪnvəˌliːd, -lɪd) /

    • a person suffering from disablement or chronic ill health

    • (as modifier): an invalid chair

  1. suffering from or disabled by injury, sickness, etc

  1. to cause to become an invalid; disable

  2. (usually foll by out; often passive) mainly British to require (a member of the armed forces) to retire from active service through wounds or illness

Origin of invalid

C17: from Latin invalidus infirm, from in- 1 + validus strong

usage For invalid

It is best to avoid using the term invalid when referring to people with chronic illnesses or disabilities

Derived forms of invalid

  • invalidity, noun

British Dictionary definitions for invalid (2 of 2)


/ (ɪnˈvælɪd) /

  1. not valid; having no cogency or legal force

  2. logic (of an argument) having a conclusion that does not follow from the premises: it may be false when the premises are all true; not valid

Origin of invalid

C16: from Medieval Latin invalidus without legal force; see invalid 1

Derived forms of invalid

  • invalidity (ˌɪnvəˈlɪdɪtɪ) or invalidness, noun
  • invalidly, adverb

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012