proof

/pɹuːf/

//pɹuːf// noun

By · According to Wiktionary data (CC BY-SA) ·

"proof" is a 5-letter English headword indexed on PlainSpell.

The verdict

“proof” has 7 generated spelling variants in the English index at frequency #2,052. The variants make it a useful spelling check.

#2,052
frequency rank, English
4,417
“P” headwords
7
tracked misspellings
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - An effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial.

Corpus desk

Index EN-proof · proof · English

proof · rank #2,052 · 7 variants · 20 confusables

  • FREQ-COMMON #2,052
  • LEN-MID 5 letters
  • VOW-2 2 vowels
  • CONFUS-HIGH 20 pairs
  • VAR-MID 7 variants
  • BOOK-MID 4,417
  • PHOTO-FINISH profit

Nearest frequency peer: profit (-1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Frequency neighbourhood for “proof”

Lower corpus rank = more everyday usage (inverted bar length for readability)

corpus weight

What this shows Bars show where “proof” sits against the nearest ranked English headwords in the FrequencyWords band, not a reprint of letter-browse containment.

Source FrequencyWords open word-frequency list As of September 3, 2026

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

proof vs pros
60% similar
proof vs prop
60% similar
proof vs Prot
40% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for proof
PropertyValue
Headwordproof
LanguageEnglish
Part of speechNoun
IPA/pɹuːf/
Letters5
Frequency rank#2,052
Misspellings tracked7
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “proof” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).proof lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

A misspelling magnet

The generator records 7 spelling variants around proof (IPA /pɹuːf/), anoun. Corpus frequency is #2,052 among 4,417 “P” headwords. Wiktionary lists 11 senses, so context still picks the gloss.

Our generated misspelling index lists 7 likely wrong-spelling variants for proof, with forms such as "porof", "pproof", and "prof". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. It also participates in 20 confusable-pair relationships, "pros", "prop", "Prot", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.

Etymologically, the entry records: From Middle English proof, from Old French prove, from Late Latin proba (“a proof”), from Latin probō (“to prove”); see prove; compare also the doublet probe. The correct English form is proof, spelled P-R-O-O-F.

Definition

  1. 1
    An effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial.
  2. 2
    The degree of evidence which convinces the mind of any truth or fact, and produces belief; a test by facts or arguments which induce, or tend to induce, certainty of the judgment; conclusive evidence; demonstration.
  3. 3
    The quality or state of having been proved or tried; firmness or hardness which resists impression, or does not yield to force; impenetrability of physical bodies.
  4. 4
    Experience of something.
  5. 5
    Firmness of mind; stability not to be shaken.
  6. 6
    A proof sheet; a trial impression, as from type, taken for correction or examination.
  7. 7
    A limited-run high-quality strike of a particular coin, originally as a test run, although nowadays mostly for collectors' sets.
  8. 8
    A sequence of statements consisting of axioms, assumptions, statements already demonstrated in another proof, and statements that logically follow from previous statements in the sequence, and which concludes with a statement that is the object of the proof.
  9. 9
    A process for testing the accuracy of an operation performed. Compare prove, transitive verb, 5.
  10. 10
    Armour of excellent or tried quality, and deemed impenetrable; properly, armour of proof.
  11. 11
    A measure of the alcohol content of liquor. Originally, in Britain, 100 proof was defined as 57.1% by volume (no longer used). In the US, 100 proof means that the alcohol content is 50% of the total volume of the liquid; thus, perfectly pure absolute alcohol would be 200 proof.

Recorded use

Wiktionary examples

These source excerpts show how proof appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. I need proof of your unconditional love. Lend me some dough.
  2. 1591, Edmund Spenser, Prosopopoia: or, Mother Hubbard's Tale, later also published in William Michael Rossetti, Humorous Poems, But the false Fox most kindly played his part, For whatsoever mother-wit or art Could work he put in proof. No practice sly, No counterpoint of cunning policy, No reach, no breach, that might him profit bring. But he the same did…

Etymology

From Middle English proof, from Old French prove, from Late Latin proba (“a proof”), from Latin probō (“to prove”); see prove; compare also the doublet probe.

This word in other languages

prueba(Español)preuve(Français)Beweis(Deutsch)

Common misspellings

Also misspelled as:

  • porof
  • pproof
  • prof
  • profo
  • prooff
  • prroof
  • rpoof

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of proof - counted as single-character edits (an insertion, a deletion, or a substituted letter). The larger the bar, the easier the typo is to spot; one-edit slips are the ones that sneak past readers.

porof2pproof1prof1profo2prooff1prroof1rpoof2
Edit distance from "proof"

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

PlainSpell is rendered directly from structured Wiktionary extracts and open word-frequency lists, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of September 3, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.

Frequently Asked Questions

How do you spell "proof"?
"proof" is spelled P-R-O-O-F. The IPA pronunciation is /pɹuːf/.
What does "proof" mean?
As a noun, "proof" means: An effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial.
What words are commonly confused with "proof"?
"proof" is commonly confused with "pros", "prop", "Prot". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "proof"?
The IPA (International Phonetic Alphabet) transcription for "proof" is /pɹuːf/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "proof"?
From Middle English proof, from Old French prove, from Late Latin proba (“a proof”), from Latin probō (“to prove”); see prove; compare also the doublet probe. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "proof", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 5 letters (nearest by frequency rank).

ocean#2,049limit#2,047Asian#2,059banks#2,061

Similar misspelling depth

Headwords with a similar count of attested misspellings (7 here; floor ≥5).

fixed7 variantsenemy7 variantschair7 variantshomes7 variants

What to do next

You've looked up "proof". Here's where to go from here.

  • "proof" maps to 20 confusable pairs in this vintage; the highest-scored is "pros". View pair
  • 7 edit-distance misspelling variants are generated for spell-check research on this headword. See variants
  • Usage frequency rank #2,052 among English headwords in this corpus. Corpus statistics
  • Browse more English words in the "P" letter cohort. P–Z browse
  • PlainSpell rotates a curated Word of the Day from the English corpus, a passive way to discover vocabulary. Word of the Day

PlainSpell is a reference corpus, not spelling advice. Verify unusual forms in context.

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list