invalid
adjective (1)Definition of invalid
(Entry 1 of 4)
: not valid:
a
: being without foundation or force in fact, truth, or law
an invalid assumption declared the will invalid
b
: logically inconsequent
invalid
nounDefinition of invalid (Entry 2 of 4)
: one who is sickly or disabled
invalid
verb
invalided; invaliding; invalids
Definition of invalid (Entry 3 of 4)
1
: to remove from active duty by reason of sickness or disability
2
: to make sickly or disabled
invalid
adjective (2)Definition of invalid (Entry 4 of 4)
1
: affected by disease or disability : sickly
2
: of, relating to, or suited to one that is sick
an invalid chair
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Merriam-Webster unabridged
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Time Traveler for invalid
The first known use of invalid was in 1542
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