Achilles heel

/əˌkɪl.iːz ˈhiːl/

//əˌkɪl.iːz ˈhiːl// noun

"achilles-heel" is a 12-letter English headword indexed on PlainSpell.

The verdict

“Achilles heel” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
13
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A vulnerability in an otherwise strong situation.

Key facts for Achilles heel
PropertyValue
HeadwordAchilles heel
LanguageEnglish
Part of speechNoun
IPA/əˌkɪl.iːz ˈhiːl/
Letters13
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “Achilles heel” sits in English frequency

Achilles heel falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

Achilles heel is uncommon English outside the top frequency list, classed as anoun, transcribed /əˌkɪl.iːz ˈhiːl/. Rarity is why readers land here mid-draft. 2 senses are on record.

We couldn't generate a plausible misspelling set for Achilles heel, and the word's spelling is regular enough that our generator found nothing worth flagging. No confusable counterpart is on file for this word, which typically means the spelling is too distinctive to be mistaken for another word.

Etymologically, the entry records: From the Greek hero Achilles, whom according to legend his mother held by the heel when she dipped him in the River Styx, making him invulnerable everywhere except on his heel. He was later killed by an arrow wound to the heel. Although the legend is ancien… The correct English form is Achilles heel, spelled A-C-H-I-L-L-E-S- -H-E-E-L.

Definition

  1. 1
    A vulnerability in an otherwise strong situation.
  2. 2
    The Achilles tendon, the tendo Achillis.

Etymology

From the Greek hero Achilles, whom according to legend his mother held by the heel when she dipped him in the River Styx, making him invulnerable everywhere except on his heel. He was later killed by an arrow wound to the heel. Although the legend is ancient, the phrase only entered English in the 19th century. It is used as a metaphor for vulnerability, as in the earliest citation, an essay by Samuel Taylor Coleridge.

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "Achilles heel"?
"Achilles heel" is spelled A-C-H-I-L-L-E-S- -H-E-E-L. The IPA pronunciation is /əˌkɪl.iːz ˈhiːl/.
What does "Achilles heel" mean?
As a noun, "Achilles heel" means: A vulnerability in an otherwise strong situation.
How do you pronounce "Achilles heel"?
The IPA (International Phonetic Alphabet) transcription for "Achilles heel" is /əˌkɪl.iːz ˈhiːl/. 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 "Achilles heel"?
From the Greek hero Achilles, whom according to legend his mother held by the heel when she dipped him in the River Styx, making him invulnerable everywhere except on his heel. He was later killed by an arrow wound to the heel. Although the legend... 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 “Achilles heel”

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

  • The one correct English spelling is A-C-H-I-L-L-E-S- -H-E-E-L - every other letter order is a misspelling in standard orthography.
  • Say it as /əˌkɪl.iːz ˈhiːl/ (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
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