valid

Adjective

valid (comparative more valid, superlative most valid)

1. Well-grounded or justifiable, pertinent.
   • I will believe him as soon as he offers a valid answer.
   • Few concepts are as emotionally charged as that of race. The word conjures up a mixture of associations—culture, ethnicity, genetics, subjugation, exclusion and persecution. But is the tragic history of efforts to define groups of people by race really a matter of the misuse of science, the abuse...2012 March-April, Jan Sapp, “Race Finished”, in American Scientist, volume 100, number 2, archived from the original on 05 Sep 2015, page 164

   Synonyms:

   arguable, groundly, proper, warrantable

2. Acceptable, proper or correct; in accordance with the rules.
   • A valid format for the date is DD/MM/YY.
   • Do not drive without a valid license.

   Synonyms:

   legit, legitimate

3. Related to the current topic, or presented within context, relevant.

   Synonyms:

   applicable, germane, apposite, apt, ad rem, well-placed, felicitous, in point, material, on point

4. Of a formula or system: such that it evaluates to true regardless of the input values.
5. Of an argument: whose conclusion is always true whenever its premises are true.
   • An argument is valid if and only if the set consisting of both (1) all of its premises and (2) the contradictory of its conclusion is inconsistent.
6. Genuine - as distinguished from efficient or regular - sacrament.