I. in·val·id (ˌ)in-ˈva-ləd adjective
Etymology: Latin invalidus weak, from in- + validus strong — more at valid
Date: 1542
: not valid:
a. : being without foundation or force in fact, truth, or law
an invalid assumption
declared the will invalid
b. : logically inconsequent
• in·val·id·ly -lē adverb
II. in·va·lid ˈin-və-ləd, Britain usually -ˌlēd adjective
Etymology: Latin & French; French invalide, from Latin invalidus
Date: 1642
1. : suffering from disease or disability : sickly
2. : of, relating to, or suited to one that is sick
an invalid chair
III. invalid same as 2 noun
Date: 1701
: one who is sickly or disabled
IV. in·va·lid ˈin-və-ləd, -ˌlid, Britain usually -ˌlēd or ˌin-və-ˈlēd transitive verb
Date: 1787
1. : to remove from active duty by reason of sickness or disability
2. : to make sickly or disabled