Synonyms of invalid

invalid 1 of 3

adjective (1)

ˈin-və-ləd 

as in fragile

chronically or repeatedly suffering from poor health

an old and now invalid woman who rarely gets out anymore

Synonyms & Similar Words

• fragile
• weak
• weakly
• sickly
• dying
• sick
• frail
• ailing
• feeble
• fading
• weakened
• incurable
• bedridden
• delicate
• incapacitated
• poorly
• moribund
• debilitated
• unhealthy
• unsound
• enfeebled
• infirm
• ill
• decrepit
• bedfast
• unwell
• indisposed
• worn-out
• peaked
• run-down

Antonyms & Near Antonyms

• well
• healthy
• whole
• sound
• wholesome
• fit
• hale
• hearty
• able-bodied
• well-conditioned

invalid

2 of 3

adjective (2)

(ˌ)in-ˈva-ləd 

1

as in null

having no legal or binding force

the treaty is invalid once one side violates it

Synonyms & Similar Words

• null
• void
• illegal
• inoperative
• null and void
• nugatory
• bad
• worthless
• useless
• nonvalid
• nonbinding
• ineffective
• ineffectual

Antonyms & Near Antonyms

• valid
• good
• legal
• binding
• working

2

as in erroneous

not being in agreement with what is true

that's an invalid assumption on your part

Synonyms & Similar Words

• erroneous
• incorrect
• inaccurate
• wrong
• false
• misleading
• untrue
• inexact
• unsound
• untruthful
• distorted
• off base
• off
• fraudulent
• deceptive
• specious
• spurious
• fictitious
• illusory
• fallacious
• counterfactual
• delusive
• dishonest
• deceitful
• unproven
• awry
• mendacious
• lying
• unconfirmed
• untested
• invented
• delusory
• amiss
• askew
• fabricated
• made-up
• trumped-up

Antonyms & Near Antonyms

• valid
• correct
• true
• proper
• right
• accurate
• exact
• sound
• precise
• factual
• confirmed
• demonstrated
• established
• tested
• errorless
• perfect
• veracious
• proven
• impeccable
• flawless
• faultless
• letter-perfect

3

as in unreasonable

not using or following good reasoning

an argument which has one untrue premise is invalid

Synonyms & Similar Words

• unreasonable
• irrational
• illegitimate
• unreasoning
• misleading
• weak
• illogical
• unreasoned
• absurd
• fallacious
• foolish
• silly
• unsound
• inconsequential
• meaningless
• inconsistent
• nonrational
• weird
• inconsequent
• unusual
• odd
• specious
• strange
• misguided
• unconsidered
• random
• sophistic
• insane
• nonsensical
• asinine
• unconvincing
• ill-advised
• disorganized
• surreal
• inexplicable
• preposterous
• mad
• disordered
• eristic
• half-baked
• wacky
• unaccountable
• unexplainable
• nutty
• senseless
• peculiar
• reasonless
• rambling
• Kafkaesque

Antonyms & Near Antonyms

• valid
• reasonable
• logical
• sound
• rational
• wise
• sensible
• sane
• justified
• informed
• sober
• reasoned
• enlightened
• well-founded
• just
• clear
• certain
• well-grounded
• solid
• plausible
• convincing
• true
• compelling
• organized
• persuasive
• sure
• credible
• commonsense
• ordered
• satisfying
• cogent
• confirmed
• demonstrated
• established
• validated
• substantiated
• corroborated

4

as in unsupported

having no basis in reason or fact

an invalid claim that can be easily disproved by the facts

Synonyms & Similar Words

• unreasonable
• unsupported
• unfounded
• baseless
• unwarranted
• unsubstantiated
• false
• irrational
• groundless
• unnecessary
• unreasoned
• absurd
• misleading
• nonvalid
• illogical
• inconsistent
• weak
• wrong
• fallacious
• meaningless
• untenable
• unconscionable
• implausible
• unsound
• unconvincing
• foundationless
• specious
• stupid
• misled
• gratuitous
• flimsy
• nonlogical
• foolish
• uncalled-for
• unwise
• silly
• nonsensical
• insane
• fatuous
• asinine
• ill-advised
• mad
• preposterous
• wacky
• simpleminded
• harebrained
• nutty
• senseless
• crazy
• brainless
• crackpot
• half-witted

Antonyms & Near Antonyms

• valid
• reasonable
• good
• hard
• justified
• reasoned
• certified
• just
• confirmed
• logical
• validated
• well-founded
• rational
• true
• substantiated
• actual
• real
• informed
• wise
• well-grounded
• certain
• sensible
• verified
• genuine
• sane
• sure
• sober
• corroborated
• clear
• solid
• plausible
• sound
• compelling
• convincing
• persuasive
• credible
• satisfying
• commonsense
• cogent

invalid

3 of 3

verb

as in to impair

Related Words

• impair
• hurt
• harm
• damage
• injure
• exhaust
• lay up
• grind (down)
• deplete
• wash out
• wear down
• wear out
• impoverish
• disable
• depress
• cripple
• unman
• hamstring
• break down
• incapacitate
• weaken
• paralyze
• waste
• enfeeble
• debilitate
• devitalize
• sap
• soften
• tire
• etiolate
• enervate
• prostrate

Dissimilar Words

• strengthen
• fortify
• recruit
• beef (up)
• energize
• season
• rejuvenate
• harden
• invigorate
• vitalize
• toughen

Example Sentences

Recent Examples of invalid

Adjective

Neither of those interpretations would be entirely invalid, exactly, and yet The Basics of Philosophy — ironically enough, given its title — mostly evades any such moral didacticism. — Richard Lawson, HollywoodReporter, 4 Sep. 2026

As a result, this route was RPKI-valid and would not be at risk of being dropped by ASes that reject RPKI-invalid routes. — Dan Goodin, ArsTechnica, 2 Sep. 2026

Verb

If this is ascertained, the BBC quotes an LA attorney saying this would render Hackman’s will invalid, and mean his children could have a claim to the estate. — Caroline Frost, Deadline, 16 Mar. 2025

DeSantis's office has said all options are on the table for their fight, but a legal ruling invaliding the agreement that currently gives Disney near-total control of the district would be the easiest resolution for the governor's headache. — Jack Birle, Washington Examiner, 8 Apr. 2023