pertinacious

/ˌpɜːtɪˈneɪʃəs/

//ˌpɜːtɪˈneɪʃəs// adj

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

The verdict

“pertinacious” is uncommon English (outside the top frequency list), classed as an adjective. The kind of spelling people second-guess.

Unranked
below top-frequency English
12
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Holding tenaciously to an opinion or purpose.

Corpus desk

Index EN-pertinacious · pertinacious · English

pertinacious · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 12 letters
  • VOW-6 6 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "P" thin
  • PHOTO-UNK Peer pending

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.

Key facts for pertinacious
PropertyValue
Headwordpertinacious
LanguageEnglish
Part of speechAdjective
IPA/ˌpɜːtɪˈneɪʃəs/
Letters12
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “pertinacious” in English

pertinaciousfalls 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

pertinacious is uncommon English outside the top frequency list, classed as anadjective, transcribed /ˌpɜːtɪˈneɪʃəs/. Rarity is why readers land here mid-draft. 2 senses are on record.

The misspelling generator found no plausible variants for pertinacious, since its letter sequence doesn't invite the usual edit-distance slips. It is not paired with a close-neighbour confusable in our dataset, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: From pertinace + -ious, from Old French pertinace, from Latin pertinax, from per- (“very”) + tenax (“tenacious”). The correct English form is pertinacious, spelled P-E-R-T-I-N-A-C-I-O-U-S.

Definition

  1. 1
    Holding tenaciously to an opinion or purpose.
  2. 2
    Stubbornly resolute or tenacious.

Recorded use

Wiktionary examples

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

  1. When that divine took his leave, not a little discomfited and amazed at the pertinacious obstinacy of the women, Laura repeated her embraces and arguments with tenfold fervour to Helen, who felt that there was a great deal of cogency in most of the latter.
  2. He would really have to make up his mind to care for his wife or not to care for her. What would Lady Vandeleur say to one alternative, and what would little Joscelind say to the other? That is what it was to have a pertinacious father and to be an accommodating son.

Etymology

From pertinace + -ious, from Old French pertinace, from Latin pertinax, from per- (“very”) + tenax (“tenacious”).

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 "pertinacious"?
"pertinacious" is spelled P-E-R-T-I-N-A-C-I-O-U-S. The IPA pronunciation is /ˌpɜːtɪˈneɪʃəs/.
What does "pertinacious" mean?
As an adjective, "pertinacious" means: Holding tenaciously to an opinion or purpose.
How do you pronounce "pertinacious"?
The IPA (International Phonetic Alphabet) transcription for "pertinacious" is /ˌpɜːtɪˈneɪʃəs/. 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 "pertinacious"?
From pertinace + -ious, from Old French pertinace, from Latin pertinax, from per- (“very”) + tenax (“tenacious”). 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.

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

Source: FrequencyWords open word-frequency list