invalid

UK: ɪnˈvælɪd | US: ɪnˈvælɪd

Definition

  1. adj. 1. Not legally or factually valid; void.

  2. adj. 2. (Of an argument or conclusion) Incorrect due to flawed logic.

  3. n. 3. A person made weak or disabled by illness or injury.

Structure
in <not>valid <legally sound>
Etymology

Derived from Latin invalidus (in- "not" + validus "strong, effective"). Originally described physical weakness (16th c.), later extended to legal/logical contexts (17th c.). The dual meanings reflect a shift from bodily incapacity to abstract invalidity.

Examples

  1. The contract was declared invalid due to missing signatures.

  2. Your assumption renders the entire argument invalid.

  3. He cared for his elderly invalid mother.

  4. An invalid password will lock the account after three attempts.

  5. The court dismissed the claim as invalid evidence.