Fiat implies a strong authoritative decision without room for negotiation or debate. The new school policy was introduced by fiat, leaving no room for discussion.
Pro Tip 2/3
Not Always Popular
Fiats can be controversial; they're not always accepted or agreed upon by everyone. The mayor's fiat on park curfews angered local residents.
Pro Tip 3/3
Implied Speed
Using 'fiat' can suggest that a decision was made quickly, bypassing usual processes. By fiat, the leader disbanded the committee without prior notice.