invalid
1 Americannoun
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an infirm or sickly person.
-
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.
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Archaic. a member of the armed forces disabled for active service.
adjective
-
unable to care for oneself due to infirmity or disability.
his invalid sister.
-
of or for invalids.
invalid diets.
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(of things) in poor or weakened condition.
the invalid state of his rocking chair.
verb (used with object)
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to affect with disease; make an invalid.
He was invalided for life.
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to remove from or classify as not able to perform active service, as an invalid.
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British. to remove or evacuate (military personnel) from an active theater of operations because of injury or illness.
verb (used without object)
adjective
-
not valid; not founded in truth, fact, or logic, and hence weak and indefensible; unsound; untenable.
The entire argument depends on an invalid assumption.
- Synonyms:
- incorrect, inaccurate, false, erroneous, unsubstantiated, unfounded, groundless, baseless
-
deficient in effectiveness; inadequate.
Self-perception is an invalid method of judging one's own biases.
-
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.
- Synonyms:
- null and void
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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.
noun
adjective
verb
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to cause to become an invalid; disable
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(usually foll by out; often passive) to require (a member of the armed forces) to retire from active service through wounds or illness
adjective
-
not valid; having no cogency or legal force
-
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
Usage
It is best to avoid using the term invalid when referring to people with chronic illnesses or disabilities
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
-
invalidsimple
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invalidssimple
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have invalidedperfect
-
has invalidedperfect
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am invalidingprogressive
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are invalidingprogressive
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is invalidingprogressive
-
have been invalidingperfect progressive
-
has been invalidingperfect progressive
Past
-
invalidedsimple
-
had invalidedperfect
-
was invalidingprogressive
-
were invalidingprogressive
-
had been invalidingperfect progressive
Future
Etymology
Origin of invalid1
First recorded in 1635–45; from French invalide, from Latin invalidus “weak, feeble, infirm”; See in- 3, valid
Origin of invalid2
First recorded in 1630–40; from Latin invalidus “weak, feeble”; see invalid 1
Explanation
A person who is very sick or injured and needs frequent care is an invalid. Also, something no longer current or useful is invalid. The main uses of this word have to do with people and things that don't work very well anymore. A driver's license that has expired is invalid — it needs to be renewed. If you lost your health insurance, it's invalid. People who are called invalids are disabled or incapacitated severely. Be careful with this word, because some think it is inappropriate, since it sounds as if some people are not as valid as others based on physical capability.
Vocabulary lists containing invalid
"Sorry, Wrong Number," Vocabulary from the play
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"Sorry, Wrong Number," Vocabulary from the play
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The Suffix -id, Part 1
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Online retailers selling the physical edition have stated that, as with other digital game codes, the one being offered for GTA 6 is single-use and will become invalid after it is redeemed.
From BBC • Jun. 26, 2026
Bellows, now Maine’s secretary of state and a gubernatorial candidate, recently struck the question from the ballot due to invalid signatures, a decision that’s now in court.
From Slate • Jun. 16, 2026
But an Alberta judge shut down the process, saying the citizens' initiative was invalid because the separatists had failed to consult with Indigenous groups whose rights could be threatened if the province separated from Canada.
From Barron's • May 25, 2026
Legal experts said the fund could be considered invalid for several reasons.
From The Wall Street Journal • May 19, 2026
They formed a little procession, Rachel and Judith supporting the invalid at each elbow, and Kit following behind to hold up the trailing ends of the quilt from the sanded floor.
From "The Witch of Blackbird Pond" by Elizabeth George Speare
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
