fallacy

/ˈfæl.ə.si/

//ˈfæl.ə.si// noun

"fallacy" is a 7-letter English headword indexed on PlainSpell.

The verdict

“fallacy” is a moderately-common English word, ranked #22,081 in English word frequency and used as a noun.

#22,081
frequency rank, English
7
letters
9
tracked misspellings
1
confusable pair

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Deceptive or false appearance; that which misleads the eye or the mind.

Visual similarity to commonly confused words

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

fallacy vs fallback
75% similar

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

Key facts for fallacy
PropertyValue
Headwordfallacy
LanguageEnglish
Part of speechNoun
IPA/ˈfæl.ə.si/
Letters7
Frequency rank#22,081
Misspellings tracked9
Confusable pairs1
SourceWiktionary (kaikki.org)

Where “fallacy” 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). fallacy lands here:

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

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

Spelling & Dictionary Insight

The English entry for fallacy is 7 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈfæl.ə.si/. Corpus data places it at rank #22,081 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 2 distinct senses for this headword, so context determines which meaning a reader should apply.

Our generated misspelling index lists 9 likely wrong-spelling variants for fallacy, with forms such as "afllacy", "falacy", and "falalcy". Each variant is a distinct typo pattern an edit-distance generator flags, typically a doubled-consonant error, a silent-letter drop, or a vowel substitution. It also participates in 1 confusable-pair relationship, "fallback", where similar look or sound leads writers to substitute one word for another in context.

Etymologically, the entry records: From Middle English fallaci, fallace, fallas, from Old French fallace, from Latin fallācia (“deception, deceit”), from fallāx (“deceptive, deceitful”), from fallere (“to deceive”). The correct English form is fallacy, spelled F-A-L-L-A-C-Y.

Definition

  1. 1
    Deceptive or false appearance; that which misleads the eye or the mind.
  2. 2
    An argument, or apparent argument, which professes to be decisive of the matter at issue, while in reality it is not; a specious argument.

Etymology

From Middle English fallaci, fallace, fallas, from Old French fallace, from Latin fallācia (“deception, deceit”), from fallāx (“deceptive, deceitful”), from fallere (“to deceive”).

This word in other languages

Common misspellings

Also misspelled as: afllacy,falacy,falalcy,fallaccy,fallacyy,fallayc,fallcay,ffallacy,flalacy

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of fallacy - 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.

afllacy2falacy1falalcy2fallaccy1fallacyy1fallayc2fallcay2ffallacy1
Edit distance from "fallacy"

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 "fallacy"?
"fallacy" is spelled F-A-L-L-A-C-Y. The IPA pronunciation is /ˈfæl.ə.si/.
What does "fallacy" mean?
As a noun, "fallacy" means: Deceptive or false appearance; that which misleads the eye or the mind.
What words are commonly confused with "fallacy"?
"fallacy" is commonly confused with "fallback". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "fallacy"?
The IPA (International Phonetic Alphabet) transcription for "fallacy" is /ˈfæl.ə.si/. 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 "fallacy"?
From Middle English fallaci, fallace, fallas, from Old French fallace, from Latin fallācia (“deception, deceit”), from fallāx (“deceptive, deceitful”), from fallere (“to deceive”). 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 “fallacy”

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

  • The one correct English spelling is F-A-L-L-A-C-Y - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈfæl.ə.si/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “fallback” - see the side-by-side comparison. fallacy vs fallback
  • Browse more English words and confusable pairs in the same reference. English words
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