Adjective

(en adjective)

Able and efficient; having the ability needed for a specific task; having the disposition to do something; permitting or being susceptible to something.

She is capable and efficient.

He does not need help; he is capable of eating on his own.

As everyone knew, he was capable of violence when roused.

That fact is not capable of proof.

(obsolete) Of sufficient capacity or size for holding, containing, receiving or taking in. Construed with of'', ''for or an infinitive.

* 1775 Samuel Johnson, A Journey to the Western Islands of Scotland'' (''Works 10.479):

He has begun a road capable of a wheel-carriage.

Adjective

(en adjective)

Well grounded or justifiable, pertinent.

*{{quote-magazine, year=2012, month=March-April

, author=(Jan Sapp) , title=Race Finished , volume=100, issue=2, page=164 , magazine=(American Scientist) citation , passage=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 of a valid biological concept?}}

I will believe him as soon as he offers a valid answer.

Acceptable, proper or correct.

A valid format for the date is MM/DD/YY.

Do not drive without a valid license.

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

(logic) Of a formula or system: such that it evaluates to true regardless of the input values.

(logic) 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.