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.

Adjective

(en adjective)

Of or relating to principles of right and wrong in behaviour, especially for teaching right behaviour.

* Nathaniel Hawthorne

She had wandered without rule or guidance in a moral wilderness.

Conforming to a standard of right behaviour; sanctioned by or operative on one's conscience or ethical judgment.

* Sir M. Hale

the wiser and more moral part of mankind

*

, title=(The Celebrity), chapter=1 , passage=The stories did not seem to me to touch life. They were plainly intended to have a bracing moral effect, and perhaps had this result for the people at whom they were aimed. They left me with the impression of a well-delivered stereopticon lecture, with characters about as life-like as the shadows on the screen, and whisking on and off, at the mercy of the operator.}}

Capable of right and wrong action.

Probable but not proved.

Positively affecting the mind, confidence, or will.