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

Because the look is rooted in personal taste, there are no hard-and-fast rules for getting started, according to Real Simple. — Lauren Jarvis-Gibson, Charlotte Observer, 23 Sep. 2026

Thus Johns’s color room is his kingdom, and there are certain hard-and-fast rules for admittance. — Vanessa Friedman, Vogue, 1 Sep. 2026

How quickly the bladder fills depends on several factors; therefore, there’s no hard-and-fast rule about how long people can go between bathroom trips. — Amber J. Tresca, Verywell Health, 14 Aug. 2026

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

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