validity

UK: /vəˈlɪdəti/ US: /vəˈlɪdɪti/ ,(və lid′i tē)

WordReference Random House Unabridged Dictionary of American English © 2025

va•lid•i•ty  (və lid′i tē), n. 

1. the state or quality of being valid:
   to question the validity of the argument.
2. legal soundness or force.

• Late Latin validitās, equivalent. to Latin valid(us) valid + -itās- -ity
• 1540–50

WordReference Random House Learner's Dictionary of American English © 2025

val•id /ˈvælɪd/   adj. 

1. sound; just;
   well-founded:
   a valid argument.
2. having proper authority;
   that can be used legally or properly;
   authoritative:
   a valid driver's license.
3. legally sound, effective, or binding:
   a valid contract.

va•lid•i•ty /vəˈlɪdɪti/  n. [uncountable]
val•id•ness, n. [uncountable] See -val-.

WordReference Random House Unabridged Dictionary of American English © 2025

val•id  (val′id), adj. 

1. sound;
   just;
   well-founded:
   a valid reason.
2. producing the desired result;
   effective:
   a valid antidote for gloom.
3. having force, weight, or cogency;
   authoritative.
4. legally sound, effective, or binding;
   having legal force:
   a valid contract.
5. Philosophy [Logic.] (of an argument) so constructed that if the premises are jointly asserted, the conclusion cannot be denied without contradiction.
6. [Archaic.] robust;
   well;
   healthy.

• Latin validus strong, equivalent. to val(ēre) to be strong + -idus -id⁴
• 1565–75

val′id•ly, adv. 
val′id•ness, n. 
Synonyms

• 3. substantial, cogent.
• 5. logical, convincing.