hard-and-fast

Synonyms

fixed, immutable, inalterable, incommutable, inflexible, invariable, unalterable, unchangeable;

Antonyms

alterable, changeable, elastic, flexible, mutable, variable;

Near Antonyms

adaptable, adjustable;

fickle, fluctuating, inconstant, uncertain, unsettled, unstable, varying;

plastic, pliable, pliant, supple, willowy;

Related Words

changeless, constant, determinate, established, set, settled, stable, steadfast, steady, unaltered, unchanging, unvarying;

immovable, unmovable;