fiat

noun

fi·​at ˈfē-ət 

-ˌat, 

-ˌät;

ˈfī-ət, 

-ˌat 

1

: an authoritative or arbitrary order : decree

government by fiat

2

: an authoritative determination : dictate

a fiat of conscience

3

: a command or act of will that creates something without or as if without further effort

According to the Bible, the world was created by fiat.

Synonyms of fiat

• decree
• edict
• ruling
• directive

Examples of fiat in a Sentence

He runs the company by fiat.

the school principal issued a fiat that caps were not to be worn inside the school, and that was that

Recent Examples on the Web

But is finishing by fiat actually finishing for real? —Joshua Rothman, New Yorker, 20 Mar. 2026

When processes break down—whether because billionaires operate above the law, presidents govern by fiat, or monopolies crush competition—that belief evaporates. —Anthony Scaramucci, Fortune, 19 Mar. 2026

Perhaps the most important impact of having term limits banned by judicial fiat has been that on national spending. —Boston Herald Editorial Staff, Boston Herald, 27 Feb. 2026

Trump loves tariffs, which are nothing more than massive tax increases imposed by fiat on America’s consumers. —Steven Greenhut, Oc Register, 27 Feb. 2026

Word History

Etymology

Latin, let it be done, 3rd singular present subjunctive of fieri to become, be done — more at be

First Known Use

circa 1631, in the meaning defined at sense 3

Phrases Containing fiat

• fiat money

Kids Definition

fiat

noun

fi·​at ˈfē-ət  -at 

-ät;

ˈfī-ət, 

-at

: an order from someone in charge

Legal Definition

fiat

noun

fi·​at ˈfē-ˌät, -ˌat, -ət; ˈfī-ˌat 

1

: decree

2

: an authoritative but arbitrary order

a brazen act of judicial fiat

—L. H. Tribe