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

(er)

Capable of producing great physical force.

Capable of withstanding great physical force.

fast moving water, wind, etc, which has a lot of power.

Determined; unyielding.

* , chapter=10

, title= The Mirror and the Lamp , passage=It was a joy to snatch some brief respite, and find himself in the rectory drawing–room. Listening here was as pleasant as talking; just to watch was pleasant. The young priests who lived here wore cassocks and birettas; their faces were fine and mild, yet really strong , like the rector's face; and in their intercourse with him and his wife they seemed to be brothers.}}

Highly stimulating to the senses.

Having an offensive or intense odor or flavor.

Having a high concentration of an essential or active ingredient.

(specifically) Having a high alcoholic content.

(grammar) Inflecting in a different manner than the one called weak, such as Germanic verbs which change vowels.

(military) Not easily subdued or taken.

(slang, US) Impressive, good.

Having a specified number of people or units.

(of a disease or symptom) (l) (very bad or intense)

* 2005 , Andrew Gaeddert, Healing Immune Disorders: Natural Defense-Building Solutions , North Atlantic Books, page 221:

Physicians may diagnosis influenza by a throat culture or blood test, which may be important if you have a particularly strong flu, if your doctor suspects pneumonia or a bacterial infection.

(mathematics, logic) Having a wide range of logical consequences; widely applicable. (Often contrasted with a statement which it implies.)