The meaning of INVALID is not valid. How to use invalid in a sentence.

1. an infirm or sickly person, esp. one who is too sick or weak to care for himself or herself. 2. unable to care for oneself due to infirmity or disability. 3. of or for invalids. 4. to make an …

INVALID definition: 1. An invalid document, ticket, law, etc. is not legally or officially acceptable: 2. An invalid…. Learn more.

If an action, procedure, or document is invalid, it cannot be accepted, because it breaks the law or some official rule. The trial was stopped and the results declared invalid. We cannot accept …

Sep 22, 2025 · invalid (comparative more invalid, superlative most invalid) Not valid; not true, correct, acceptable or appropriate. Your argument is invalid because it uses circular …

Definition of invalid adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

noun 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. Archaic., a member of the armed forces …