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• hard-and-fast
  hard-and-fast

  adjective

  strongly binding; not to be set aside or violated.
• hard and fast
  hard and fast

  adjective

  (hard-and-fast when prenominal) (esp of rules) invariable or strict

hard-and-fast

American  

[hahrd-n-fast, -fahst] / ˈhɑrd nˈfæst, -ˈfɑst /

adjective

1. strongly binding; not to be set aside or violated.

   hard-and-fast rules.

   Synonyms:

   unambiguous, rigorous, inviolable, inflexible, precise, fixed

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hard and fast British  

adjective

1. (hard-and-fast when prenominal) (esp of rules) invariable or strict

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hard and fast Idioms  

1. Defined, fixed, invariable, as in We have hard and fast rules for this procedure. This term originally was applied to a vessel that has come out of water, either by running aground or being put in dry dock, and is therefore unable to move. By the mid-1800s it was being used figuratively.

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Other Word Forms

• hard-and-fastness
  noun

Etymology

Origin of hard-and-fast

First recorded in 1865–70

Example Sentences

See Examples For:

hard-and-fast hard and fast

But he said that it’s not clear whether this is a hard-and-fast rule.

From MarketWatch ● Sep. 4, 2026

This is why the broadcast limit is not really a hard-and-fast limit.

From BBC ● Mar. 30, 2026

Also, California has few hard-and-fast rules on residency.

From The Wall Street Journal ● Jan. 25, 2026

I do not like making hard-and-fast predictions, but this is one I am going to stick with—you’ve got it in print, right here.

From Slate ● Sep. 12, 2024

Unfortunately, there’s no hard-and-fast rule that tells you how to form the plural of every word that ends in o.

From "Woe Is I" by Patricia T. O'Conner

There’s no hard and fast rule for how quickly, or not, airlines have to act if they are going to cancel a mistake fare.

From The Wall Street Journal ● Apr. 22, 2026

You warned that what we believed to be hard and fast rules protecting the free press were really just soft norms.

From Slate ● Feb. 24, 2026

Aside from notifying customers and regulators about breaches, there are no hard and fast rules on what companies should do for victims.

From BBC ● Nov. 24, 2025

Some retail investors feel safer seeking out larger firms with well-known brands rather than boutique investment firms, but there is no hard and fast rule that says one is better than the other.

From MarketWatch ● Nov. 17, 2025

The plane lifted off, rose hard and fast, and cleared the rockets.

From "Boots on the Ground: America's War in Vietnam" by Elizabeth Partridge