proof

1 of 3

noun

ˈprüf

Synonyms of proof next

: the cogency of evidence that compels acceptance by the mind of a truth or a fact

: the process or an instance of establishing the validity of a statement especially by derivation from other statements in accordance with principles of reasoning

obsolete : experience

: something that induces certainty or establishes validity

archaic : the quality or state of having been tested or tried

especially : unyielding hardness

: evidence operating to determine the finding or judgment of a tribunal

plural proofs or proof : a copy (as of typeset text) made for examination or correction

: a test impression of an engraving, etching, or lithograph

: a coin that is struck from a highly polished die on a polished planchet, is not intended for circulation, and sometimes differs in metallic content from coins of identical design struck for circulation

: a test photographic print made from a negative

: a test applied to articles or substances to determine whether they are of standard or satisfactory quality

: the minimum alcoholic strength of proof spirit

: strength with reference to the standard for proof spirit

specifically : alcoholic strength indicated by a number that is twice the percent by volume of alcohol present

whiskey of 90 proof is 45 percent alcohol

proof

2 of 3

adjective

: able to resist or repel

boots that were … proof against cold and wet—

Robertson Davies

—often used in combination

windproof

: used in proving or testing or as a standard of comparison

: of standard strength or quality or alcoholic content

proof

3 of 3

verb

proofed; proofing; proofs

transitive verb

: to make or take a proof or test of

: proofread

: to give a resistant quality to

: to activate (yeast) by mixing with water and sometimes sugar or milk

proofer noun

Example Sentences

Noun The document was proof that her story was true. He claims that he was home when the murder was committed, but he has no proof. The proof shows that the theorem is true. Verb She proofed the story carefully.

Recent Examples on the Web

Noun

If the return is electronically filed, get a copy and ask for proof it was submitted. —

Michelle Singletary, Washington Post, 3 Mar. 2023 Look no further than the hashtag #PamCore on TikTok for proof of users emulating her iconic bang updo hairstyle or signature smoldering smoky eyes. —

Samantha Simon, ELLE, 27 Feb. 2023 For proof, Sewald looked across the room at first baseman Ty France, who has never stolen a base in his career. —

Bob Nightengale, USA TODAY, 26 Feb. 2023 For proof, see pictures of her partying at carnival in Rio de Janeiro, flashing her trademark megawatt smile. —

Alice Cary, Glamour, 22 Feb. 2023 For proof, look no further than the annual census that the district — like all others in the state — took in October, which counted fewer than 49,000 students. —

Christopher Huffaker, BostonGlobe.com, 21 Feb. 2023 Look no further than the classic yellowware bowl for proof that blue and yellow make for a timeless country combo, as seen here in this 98-square-foot galley kitchen that features canary-yellow cabinets and quilt-like cement tiles. —

Jennifer Kopf, Country Living, 10 Feb. 2023 For proof, take note of (Di)vision’s camo print long shorts, Selam Fessahaye’s cocoon-like coat dress, and Helmstedt’s abstract rainbow print. —

Kristen Bateman, refinery29.com, 6 Feb. 2023 For proof, have a look at the entryway in the photo above. —

Will Mcgough, Forbes, 23 Jan. 2023

Adjective

His companies have also produced nearly 200,000 bullet-proof vests and armored shelters for the Ukrainian army. —

Kerry A. Dolan, Forbes, 23 Feb. 2023 Authorities said the guard was wearing a bullet-proof vest at the time of the shooting. —

Louis Casiano, Fox News, 15 Feb. 2023 He was shot in both arms, and also reportedly in his bullet-proof vest. —

Carol Robinson | Crobinson@al.com, al, 17 Oct. 2022 Best of Beauty Breakthrough winner is ideal for those who want a smudge-proof formula without turning to a full-on waterproof formula. —

Michelle Rostamian, Allure, 5 Jan. 2023 Getting ahead of the durability and oxidation issues other shower caddies may be prone to, this one is made of stainless steel wire that’s thicker than standard and coated with rust-proof paint. —

Quincy Bulin, Better Homes & Gardens, 4 Jan. 2023 Apple, long notorious for making repair-proof devices, opened an online store for iPhone repair kits in April and expanded it to some MacBook parts in August. —

Rob Pegoraro, PCMAG, 29 Dec. 2022 While there are tons of great Valentine's Day desserts to choose from, cookies are one of the easiest and most fail-proof options. —

Katie Bourque, Good Housekeeping, 28 Dec. 2022 In the state legislature, Democrats actually increased their control with one extra seat in the Senate to a veto-proof margin of 24 -12 and by one seat in the state House of Representatives to 98-53. —

Christopher Keating, Hartford Courant, 25 Dec. 2022

Verb

This waterproof rain jacket is proof your rainy day fit can — and should — look runway-ready chic. —

Marissa Miller, Travel + Leisure, 13 Mar. 2023 There are a ton of products on the market that can be used to cat-proof a home. —

Courtney Vinopal, Washington Post, 2 Mar. 2023 Recession-proof your life: The tsunami of economic news in 2022 is leading consumers, investors and would-be homeowners alike to ask whether a recession is inevitable. —

Michelle Singletary, Washington Post, 31 Jan. 2023 That would Trump-proof the trans-Atlantic alliance, keeping it strong no matter who occupies the Oval Office, and perhaps prevent the defense budget from continuing to balloon ever higher. —

Matthew Duss, The New Republic, 4 Jan. 2023 After Russia’s annexation of Crimea in 2014, amid growing discord with the West, Russia began working to sanctions-proof its defense sector. —

Fred Weir, The Christian Science Monitor, 19 Dec. 2022 Both the Insulated Jacket and Weather Jacket that will winter-proof you for any outdoor adventure, for instance, are 40% off. —

Maverick Li, Men's Health, 1 Dec. 2022 To proceed with a case, prosecutors need proof a fire was arson and that a specific person started it, Allen said. —

Dallas News, 27 July 2022 Add the yeast and warm milk to a mixing and let stand for 7 minutes to proof. —

Kristianne Hannemann, USA TODAY, 2 Dec. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'proof.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

Etymology

Noun

Middle English prof, prove, alteration of preve, from Anglo-French preove, from Late Latin proba, from Latin probare to prove — more at prove

First Known Use

Noun

13th century, in the meaning defined at sense 1a

Adjective

1583, in the meaning defined at sense 1

Verb

circa 1699, in the meaning defined at sense 1a

Time Traveler

The first known use of proof was in the 13th century

See more words from the same century

Cite this Entry

Style

“Proof.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proof. Accessed 26 Mar. 2023.

Copy Citation

Kids Definition

proof

1 of 3 noun

ˈprüf

: evidence of truth or correctness

gave proof of her statement

: an act or process of showing or finding out that something is true especially by reasoning or by experiment

a proof that the theorem is true

put a theory to the proof

: a copy (as of something set in type) taken for study and correction

: a test print made from a photographic negative

proof

2 of 3 adjective

: designed or made to prevent or keep out something that could be harmful

this lock is proof against tampering

—often used in compounds

waterproof

proof

3 of 3 verb

: to activate (yeast) by mixing with water

Legal Definition

proof

noun

: the effect of evidence sufficient to persuade a reasonable person that a particular fact exists see also evidence

: the establishment or persuasion by evidence that a particular fact exists see also burden of proof

: something (as evidence) that proves or tends to prove the existence of a particular fact see also clear and convincing, preponderance of the evidence, reasonable doubt, standard of proof compare allegation, argument

: probate sense 1a

Etymology

Noun

alteration of Middle English preove, from Old French preuve, from Late Latin proba, from Latin probare to prove