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-adj)

Free of flaws or imperfections; unsullied.

* (1800-1859)

Such was the origin of a friendship as warm and pure as any that ancient or modern history records.

(senseid)Free of foreign material or pollutants.

* (Isaac Watts) (1674-1748)

A guinea is pure gold if it has in it no alloy.

Free of immoral behavior or qualities; clean.

* Bible, v. 22

Keep thyself pure .

(label) Done for its own sake instead of serving another branch of science.

* {{quote-magazine, date=2014-06-21, volume=411, issue=8892, magazine=(The Economist)

, title= Magician’s brain , passage=The [Isaac] Newton that emerges from the [unpublished] manuscripts is far from the popular image of a rational practitioner of cold and pure reason. The architect of modern science was himself not very modern. He was obsessed with alchemy.}}

(label) Of a single, simple sound or tone; said of some vowels and the unaspirated consonants.

(label) Without harmonics or overtones; not harsh or discordant.