immutable

adjectiveC1Rare in speech; mostly a word you read · #13,264 of 15,258neutral

Immutable means never changing, and unable to be changed. An immutable law, immutable facts, immutable characteristics.

In equality law, immutable characteristics are the ones a person cannot change and should not be judged on. In programming an immutable value cannot be altered after it is made, which removes a whole class of bugs.

Definitions of immutable

1adjectiveimmutableNever changing, and unable to be changed.C1
“The laws of physics are immutable; you can't argue with gravity.”

immutable is a quality.

Where it comes from

Latin immutabilis is in-, not, plus mutare, to change.

Latin
immūtābilis — unchangeable
Middle English
immutable
English, today
immutable

From Middle English immutable, from Latin immūtābilis (“unchangeable”); im- + mutable.

Etymology from Wiktionary, CC BY-SA

Practise this word

immutable in the wild

Value objects should be immutable: this is required for the implicit contract that two value objects created equal, should remain equal.
Value object
But God is absolutely immutable, as has been demonstrated.
Immutability of God in Christianity
Among other things, the chattr command is useful to make files immutable so that password files and certain system files cannot be erased during software upgrades.
Chattr
In object-oriented programming, "immutable interface" is a pattern for designing an immutable object.
Immutable interface
The immutable interface pattern involves defining a type which does not provide any methods which mutate state.
Immutable interface

From Wikipedia, CC BY-SA 4.0. These sentences were written by other people about their own subjects; they are here to show the word at work, not as anybody’s opinion.

Related words

mutable

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