valid

adjective Etymology: Middle French or Medieval Latin; Middle French valide, from Medieval Latin validus, from Latin, strong, potent, from valēre Date: 1571 1. having legal efficacy or force; especially executed with the proper legal authority and formalities <

a valid contract

> 2. a. well-grounded or justifiable ; being at once relevant and meaningful <

a valid theory

> b. logically correct <

a valid argument

> <

valid inference

> 3. appropriate to the end in view ; effective <

every craft has its own valid methods

> 4. of a taxon conforming to accepted principles of sound biological classification • validity noun • validly adverb Synonyms: valid, sound, cogent, convincing, telling mean having such force as to compel serious attention and usually acceptance. valid implies being supported by objective truth or generally accepted authority <

a valid reason for being absent

> <

a valid marriage

>. sound implies a basis of flawless reasoning or of solid grounds <

a sound proposal for reviving the economy

>. cogent may stress either weight of sound argument and evidence or lucidity of presentation <

the prosecutor's cogent summation won over the jury

>. convincing suggests a power to overcome doubt, opposition, or reluctance to accept <

a convincing argument for welfare reform

>. telling stresses an immediate and crucial effect striking at the heart of a matter <

a telling example of bureaucratic waste

>.