infallibly

/ɪnˈfæl.ɪ.bli/

//ɪnˈfæl.ɪ.bli// adv

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

"infallibly" is a 10-letter English headword indexed on PlainSpell.

The verdict

“infallibly” is uncommon English (frequency #98,258 among 2,140 “I” headwords), classed as an adverb. The kind of spelling people second-guess.

#98,258
frequency rank, English
2,140
“I” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - In an infallible manner.

Corpus desk

Index EN-infallibly · infallibly · English

infallibly · rank #98,258 · 0 variants · 0 confusables

  • FREQ-RARE #98,258
  • LEN-MEGA 10 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 2,140
  • PHOTO-FINISH ineffectively

Nearest frequency peer: ineffectively (-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.

Long-tail ranks near “infallibly”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “infallibly” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for infallibly
PropertyValue
Headwordinfallibly
LanguageEnglish
Part of speechAdverb
IPA/ɪnˈfæl.ɪ.bli/
Letters10
Frequency rank#98,258
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “infallibly” in English

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

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

Scale is logarithmic (each tick is 10× rarer). Rare peers in the same band: “ineffectively” (#98,257), “industrialize” (#98,256), “infotech” (#98,260). Among 2,140 “I” headwords, “infallibly” is #98,258. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

infallibly is uncommon English at frequency #98,258 among 2,140 “I” headwords, classed as anadverb, transcribed /ɪnˈfæl.ɪ.bli/. Rarity is why readers land here mid-draft. Gloss: "In an infallible manner.".

infallibly doesn't appear in our generated misspelling index, a straightforward case of a spelling with little room for common typos. Our dataset records no confusable match here, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: From infallible + -ly. The correct English form is infallibly, spelled I-N-F-A-L-L-I-B-L-Y.

Definition

  1. 1
    In an infallible manner.

Recorded use

Wiktionary examples

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

  1. The pope speaks infallibly ex cathedra.
  2. [I]n such way [the formation of political clubs], most infallibly of all, does Social Unrest exhibit itself; find solacement, and also nutriment.

Etymology

From infallible + -ly.

This word in other languages

infaliblemente(Español)infailliblement(Français)fehlerfrei(Deutsch)

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 "infallibly"?
"infallibly" is spelled I-N-F-A-L-L-I-B-L-Y. The IPA pronunciation is /ɪnˈfæl.ɪ.bli/.
What does "infallibly" mean?
As an adverb, "infallibly" means: In an infallible manner.
How do you pronounce "infallibly"?
The IPA (International Phonetic Alphabet) transcription for "infallibly" is /ɪnˈfæl.ɪ.bli/. 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 "infallibly"?
From infallible + -ly. 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 "infallibly", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 10 letters (nearest by frequency rank).

Hofmeister#98,227heliotrope#98,214Hattersley#98,208Kentuckian#98,314

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

Source: FrequencyWords open word-frequency list