What does unmodifiable mean?
Unmodifiable means unable to be changed, altered, or otherwise modified. It is a formal adjective used when something is intended or required to remain fixed, whether that thing is a physical object, an abstract principle, a legal arrangement, or a digital record. For example, a work described as unmodifiable cannot be edited or revised, while an unmodifiable system setting remains fixed by its design or restrictions. The word is closely related in meaning to immutable, unalterable, and unchangeable, although it is less common than those alternatives. In computing, immutable is generally the more familiar term, but unmodifiable can likewise describe data or settings that cannot be altered. Unmodifiable should not be confused with modifiable, its opposite. It is especially useful when the permanence of something is itself significant, as in statements about originals, protected records, constitutional rules, or experimental conditions.
adjectiveUnable to be changed, altered, or modified; fixed and immutable.
- Incapable of being changed, altered, or modified.
"The original copy is unmodifiable, but later versions can be revised."
"The original copy is unmodifiable, but later versions can be revised."
"Under the agreement, the settlement boundaries remained unmodifiable during the following decade."
The prefix un- flips modify into its opposite: where modify means to change, unmodifiable means unable to be changed.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does unmodifiable come from?
Unmodifiable was formed in English by combining the negative prefix un- with modify and the suffix -able. Modify comes through Old French from Latin modificare, a word derived from modus, meaning measure, manner, or limit. The same Latin foundation produced related English forms such as modification and modifier.
How unmodifiable is actually used
Unmodifiable is formal and relatively uncommon. In legal, scientific, and computing contexts, immutable is often more usual, especially for a digital object that cannot be changed after creation.
Easily confused with unmodifiable
Modifiable means capable of being changed, whereas unmodifiable means unable to be changed.