Adjective

(en adjective)

Having to substance; actually existing; real; as, substantial life.

Not seeming or imaginary; not illusive; real; solid; true; veritable.

* "to do some substantial good, is the compensation for much incidental imperfection" - Cardinal Newman, The Rise and Progress of Universities

Corporeal; material; firm.

Having good substance; strong; stout; solid; firm; as, substantial cloth; a substantial fence or wall.

possessed of goods or an estate; moderately wealthy; responsible; as, a substantial freeholder.

Large in size, quantity, or value; as, a substantial amount of money; vast

Most important; essential.

Ample or full.

A substantial amount of people in this buliding

Significantly great.

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.