foolproof

/ˈfuːl ˌpɹuːf/

//ˈfuːl ˌpɹuːf// adj

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

"foolproof" is a 9-letter English headword indexed on PlainSpell.

The verdict

“foolproof” has 13 generated spelling variants in the English index at frequency #34,062. The variants make it a useful spelling check.

#34,062
frequency rank, English
18,613
“F” headwords
13
tracked misspellings

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Of a device: protected against, or designed to be proof against, misuse or error.

Key facts for foolproof
PropertyValue
Headwordfoolproof
LanguageEnglish
Part of speechAdjective
IPA/ˈfuːl ˌpɹuːf/
Letters9
Frequency rank#34,062
Misspellings tracked13
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “foolproof” 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). foolproof 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 13 spelling variants around foolproof (IPA /ˈfuːl ˌpɹuːf/), anadjective. Corpus frequency is #34,062 among 18,613 “F” headwords. Wiktionary lists 2 senses, so context still picks the gloss.

Our generated misspelling index lists 13 likely wrong-spelling variants for foolproof, with forms such as "ffoolproof", "foloproof", and "folproof". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. We don't track a confusable pairing for this entry, suggesting its spelling stands apart enough that readers rarely confuse it with something else.

Etymologically, the entry records: From fool + -proof. The correct English form is foolproof, spelled F-O-O-L-P-R-O-O-F.

Definition

  1. 1
    Of a device: protected against, or designed to be proof against, misuse or error.
  2. 2
    Of an idea or plan: certain to succeed in all eventualities, or claimed to be so; infallible.

Etymology

From fool + -proof.

This word in other languages

seguro(Español)infaillible(Français)narrensicher(Deutsch)

Common misspellings

Also misspelled as:

  • ffoolproof
  • foloproof
  • folproof
  • foollproof
  • foolporof
  • foolpproof
  • foolprof
  • foolprofo
  • foolprooff
  • foolprroof
  • foolrpoof
  • fooplroof
  • ofolproof

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of foolproof - measured in single-character edits (insert, delete, or substitute a letter). Larger bars are easier to catch; one-edit slips are the sneakiest.

ffoolproof1foloproof2folproof1foollproof1foolporof2foolpproof1foolprof1foolprofo2
Edit distance from "foolproof"

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.

Frequently Asked Questions

How do you spell "foolproof"?
"foolproof" is spelled F-O-O-L-P-R-O-O-F. The IPA pronunciation is /ˈfuːl ˌpɹuːf/.
What does "foolproof" mean?
As an adjective, "foolproof" means: Of a device: protected against, or designed to be proof against, misuse or error.
What are common misspellings of "foolproof"?
Common misspellings include "ffoolproof", "foloproof", "folproof", "foollproof", "foolporof". The correct spelling is "foolproof".
How do you pronounce "foolproof"?
The IPA (International Phonetic Alphabet) transcription for "foolproof" is /ˈfuːl ˌpɹuːf/. 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 "foolproof"?
From fool + -proof. 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.

Using “foolproof”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is F-O-O-L-P-R-O-O-F - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈfuːl ˌpɹuːf/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words

Same frequency band

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 FrequencyWords open word-frequency list