invalid

Other forms: invalids; invalided; invaliding; invalidly

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 Also, something no longer current or useful is invalid.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.

Definitions of invalid

1. adjective

   no longer valid
   “the license is invalid”

   synonyms:

   expired

   having come to an end or become void after passage of a period of time
2. adjective

   having no cogency or legal force
   “invalid reasoning”

   “an invalid driver's license”

   synonyms:

   illegitimate

   of marriages and offspring; not recognized as lawful

   bad, uncollectible

   not capable of being collected

   fallacious, unsound

   containing or based on a fallacy

   false

   erroneous and usually accidental

   invalidated, nullified

   deprived of legal force

   null, void

   lacking any legal or binding force

   sophistic, sophistical

   plausible but misleading

   antonyms:

   valid

   well grounded in logic or truth or having legal force

   legitimate

   of marriages and offspring; recognized as lawful

   reasonable, sensible

   showing reason or sound judgment

   binding

   executed with proper legal authority

   effectual, legal, sound

   having legal efficacy or force

   legitimate, logical

   based on known statements or events or conditions

   reasoned, sound, well-grounded

   logically valid

   validated

   declared or made legally valid