invalid

UK:**UK and possibly other pronunciationsUK and possibly other pronunciations noun: /ˈɪnvəlɪd/, adjective: /ɪnˈvælɪd/

US:USA pronunciation: IPAUSA pronunciation: IPA/ˈɪnvəlɪd/

US:USA pronunciation: respellingUSA pronunciation: respelling(in′və lid, Brit. in′və lēd′ for 1; in val′id for 2)



WordReference Random House Learner's Dictionary of American English © 2026
in•va•lid1 /ˈɪnvəlɪd/USA pronunciation   n. [countable]
  1. an unhealthy person, esp. one who is too sick or weak to care for himself or herself.

adj. 
  1. unable to care for oneself, as through ill health.
  2. of or for invalids.

v. [~ + object]
  1. to make (someone) an invalid.
  2. Military[Chiefly Brit.]to evacuate (military personnel) from an area of fighting because of injury or illness.

in•val•id2 /ɪnˈvælɪd/USA pronunciation   adj. 
  1. not valid; without force or a firm foundation;
    that cannot be defended;
    weak in logic:an invalid conclusion.
  2. empty or without legal force:The contract was declared invalid.
in•va•lid•i•ty /ˌɪnvəˈlɪdɪti/USA pronunciation  n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2026
in•va•lid1  (in′və lid; Brit. in′və lēd′),USA pronunciation n. 
  1. an infirm or sickly person.
  2. a person who is too sick or weak to care for himself or herself:My father was an invalid the last ten years of his life.
  3. [Archaic.]a member of the armed forces disabled for active service.

adj. 
  1. unable to care for oneself due to infirmity or disability:his invalid sister.
  2. of or for invalids:invalid diets.
  3. (of things) in poor or weakened condition:the invalid state of his rocking chair.

v.t. 
  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.
  3. Military[Brit.]to remove or evacuate (military personnel) from an active theater of operations because of injury or illness.

v.i. Archaic. 
  1. to become an invalid.
  • Latin invalidus weak. See in-3, valid
  • French invalide
  • 1635–45

in•val•id2  (in val′id),USA pronunciation adj. 
  1. not valid;
    without force or foundation;
    indefensible.
  2. deficient in substance or cogency;
    weak.
  3. void or without legal force, as a contract.
  • Medieval Latin invalidus, Latin: weak; see invalid1
  • 1625–35
in•val′id•ly, adv. 
in•val′id•ness, n. 

Collins Concise English Dictionary © HarperCollins Publishers::
invalid /ˈɪnvəlɪd/ n
    • a person with disablement or chronic ill health
    • (as modifier): an invalid chair
 adj
  1. incapacitated or disabled by injury, sickness, etc
 vb (transitive)
  1. to cause to become an invalid; disable
  2. (usually followed by out; often passive) chiefly Brit to require (a member of the armed forces) to retire from active service through wounds or illness
Etymology: 17th Century: from Latin invalidus infirm, from in-1 + validus strong
ˌinvaˈlidity n
invalid /ɪnˈvælɪd/ adj
  • not valid; having no cogency or legal force
  • (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
    • Etymology: 16th Century: from Medieval Latin invalidus without legal force; see invalid1invalidity /ˌɪnvəˈlɪdɪtɪ/, inˈvalidness n inˈvalidly adv
    'invalid' also found in these entries (note: many are not synonyms or translations):
    confute - disallow - fallacy - false - fault - garbage - garbage collection - infirm - informal vote - null - nullity - paralogism - quash - retract - sophistry - spoliation - syllogism - valid - void - watcher - bad - bed - cancel - care - cater - challenge - chronic - commode - constitutionally - damn - deface - disconfirm - Donatist - ground - half-invalid - helpless - humor - invalidate - invalidism - invalidity - patient - redargue - reordination - unreality - valetudinarian - vitiate - weak - solemn vow

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