hard-and-fast

adjective

ˌhärd-ᵊn-ˈfast 

: not to be modified or evaded : strict

a hard-and-fast rule

Synonyms of hard-and-fast

• certain
• stable
• final
• unchanging
• unchangeable
• fixed
• hard

Examples of hard-and-fast in a Sentence

hard-and-fast rules that governed the corporate environment in those days included strictures regarding office dress that were rigidly enforced

hard-and-fast beliefs that are the rock-solid foundation of their religion

Recent Examples on the Web

The subject does not have a lot of hard-and-fast rules; wars share common characteristics but each conflict has its own peculiarities and exigent circumstances. — Tom Nichols, The Atlantic, 8 July 2026

In an television age where genre seems increasingly like a suggestion rather than a hard-and-fast rule, the Emmys are often the lone arbiter of whether a show is essentially a drama or a comedy. — Joe Reid, Vulture, 20 June 2026

However, the collagen jelly mask became the exception to my hard-and-fast rule. — Irene Richardson, InStyle, 6 June 2026

There’s no hard-and-fast rule on how physically close a witness should be under recall status, and these restrictions are up to a judge. — Frank Landymore, Futurism, 14 May 2026

Word History

First Known Use

1822, in the meaning defined above

Rhymes for hard-and-fast

• chloroplast
• epiblast
• fibroblast
• opencast
• overcast
• protoplast
• rebroadcast
• telecast
• trophoblast
• ultrafast
• unsurpassed
• aghast

Kids Definition

hard-and-fast

adjective

ˌhärd-ᵊn-ˈfast

: not to be changed : fixed

a hard-and-fast rule