Adjective

(en adjective)

Of, relating to, or connected with muscles.

* 1912 , , A Princess of Mars , chapter 2

It was an effort of the mind, of the will, of the nerves; not muscular , for I could not move even so much as my little finger, but none the less mighty for all that.

Brawny, thewy, having strength.

* 1843 , , Stave Two

The arms were very long and muscular ; the hands the same, as if its hold were of uncommon strength.

Having large, well-developed muscles.

(figurative) Strong, robust.

* 2014 June 9, Samanth Subramanian, " India After English?" (blog post), nybooks.com:

Future prime ministers may struggle to replicate the sort of muscular countrywide support that Modi was able to earn.

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.