What does unalterable mean?
Unalterable is a formal adjective meaning unable to be changed, altered, or modified. It describes something whose nature, status, or principles are fixed: an unalterable fact, an unalterable tradition, or a code that cannot be modified. The word is especially common in legal, political, scientific, and philosophical discussion, where it emphasizes resistance to revision or compromise. Its tone is authoritative and absolute, often stronger and more rhetorical than "changeable" or simply "fixed." In ordinary conversation it can sound formal, so writers may choose "immutable," "permanent," or "unchangeable" when those precise shades matter. Knowing "unalterable" is nevertheless useful because it captures a clear distinction between what is merely unchanged at present and what cannot be changed at all. It also makes the contrast with "alterable" immediately visible, which gives the word a compact, emphatic quality.
adjectiveUnable to be changed, altered, or modified; fixed and impervious to revision.
- Incapable of being changed, altered, or modified; fixed and unchangeable.
"The commission maintained that the historical record was unalterable and should not be rewritten."
"The treaty was regarded as unalterable once the final provisions had been signed."
"Some scientists use the term absolute zero to describe a theoretically unalterable minimum temperature."
One small prefix turns the ability to change into an absolute refusal to change.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does unalterable come from?
The adjective was formed in English by adding the prefix un- to alterable. Alterable comes from Latin alterabilis, meaning "changeable," and is related to Latin alter, "other," from a Proto-Indo-European root meaning "other." Latin and English cognates helped establish the broader family represented by alteration and alternative.
Related word forms
How unalterable is actually used
Formal and often emphatic. It is especially common in legal, political, scientific, and philosophical contexts. In informal writing, "immutable," "fixed," or "unchangeable" may sound more natural.
Easily confused with unalterable
"Unaltered" describes something that has not changed; "unalterable" describes something that cannot be changed.