invariable
[adjective]
Synonyms: inflexible, constant, fixed, immovable, immutable, inalterable, unalterable, unchangeable, unmodifiable, unmovable, same, consistent, unchanging, unfailing, unvarying

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Antonyms: variable, varying

[TahlilGaran] English Synonym Dictionary ▲

in‧var‧i‧a‧ble AC /ɪnˈveəriəbəl $ -ˈver-/ adjective
[Word Family: noun: variable, variance, variant, variety, variability, variation; adjective: variable ≠ invariable, varied, various; adverb: variably ≠ invariably, variously; verb: vary]

1. always happening in the same way, at the same time etc:
His invariable answer was ‘Wait and see.’

2. technical never changing Antonym : variable:
Mass, unlike weight, is invariable.

[TahlilGaran] Dictionary of Contemporary English ▲