irreversible

adjective

ir·​re·​vers·​ible ˌir-i-ˈvər-sə-bəl How to pronounce irreversible (audio)
Synonyms of irreversiblenext
: not reversible
irreversibility
ˌir-i-ˌvər-sə-ˈbi-lə-tē How to pronounce irreversible (audio)
noun
irreversibly
ˌir-i-ˈvər-sə-blē How to pronounce irreversible (audio)
adverb

Synonyms of irreversible

Relevance
See All Synonyms & Antonyms in Thesaurus

Examples of irreversible in a Sentence

He suffered an irreversible loss of vision. The crisis has done irreversible harm to the countries' relations.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Before taking an irreversible step, the School Board should give communities time to examine alternatives. — Tim Lonergan, Sun Sentinel, 29 Oct. 2026 The plaintiffs challenging the project, DC Preservation League and two golfers, claim the work is inflicting irreversible damage. — Michael Kunzelman, Los Angeles Times, 27 Oct. 2026 Scientists debate the threshold beyond which the dense, humid Amazon rainforest could shift to a drier ecosystem, with irreversible consequences for biodiversity and the climate. — ABC News, 27 Oct. 2026 Governance forums multiply because nobody quite wants to make the irreversible call. — Kelvin Cheema, Forbes.com, 26 Oct. 2026 See All Example Sentences for irreversible

Word History

First Known Use

1630, in the meaning defined above

Time Traveler
The first known use of irreversible was in 1630

Rhymes for irreversible

See All Rhymes for irreversible

Browse Nearby Words

irreversibility
irreversible
irrevocability
See all Nearby Words

Cite this Entry

“Irreversible.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/irreversible. Accessed 31 Oct. 2026.

Copy Citation

Kids Definition

irreversible

adjective
ir·​re·​vers·​ible ˌir-i-ˈvər-sə-bəl How to pronounce irreversible (audio)
: impossible to reverse
an irreversible chemical reaction
irreversible damage
irreversibility
-ˌvər-sə-ˈbil-ət-ē How to pronounce irreversible (audio)
noun
irreversibly
-ˈvər-sə-blē How to pronounce irreversible (audio)
adverb

Medical Definition

irreversible

adjective
ir·​re·​vers·​ible ˌir-i-ˈvər-sə-bəl How to pronounce irreversible (audio)
: incapable of being reversed : not reversible
an irreversible medical procedure
: as
a
: impossible to make run or take place backward
irreversible chemical syntheses
b
of a colloid : incapable of undergoing transformation from sol to gel or vice versa
c
of a pathological process : of such severity that recovery is impossible
irreversible brain damage
irreversibility
-ˌvər-sə-ˈbil-ət-ē How to pronounce irreversible (audio)
noun
plural irreversibilities
irreversibly
-ˈvər-sə-blē How to pronounce irreversible (audio)
adverb

Legal Definition

irreversible

adjective
ir·​re·​ver·​si·​ble ˌir-rə-ˈvər-sə-bəl How to pronounce irreversible (audio)
: not reversible
an irreversible decision
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Last Updated: - Updated example sentences

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of wraith

See Definitions and Examples »

Popular in Grammar & Usage

See More

How to Use 'Who' vs. 'Whom'

Merriam-Webster’s Great Big List of Words You Love to Hate

'Affect' vs. 'Effect'

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?
See More

Popular in Wordplay

See More

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

Pwn, Skibidi, Girlboss and Other Words Added to the 2026 Scrabble Dictionary

The Words of the Week - Oct. 30

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

How to Use 'Who' vs. 'Whom'

The Longest Long Words List

9 Words That Sound Like Insults But Aren't
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
different halloween monsters in silhouette
A Monstrous Vocab Quiz Words That Go Bump in the Night
See All