assiduous
/əˈsɪdjuːəs/
"assiduous" is a 9-letter English headword indexed on PlainSpell.
The verdict
“assiduous” is uncommon English (frequency #79,273 among 3,931 “A” headwords), classed as an adjective. The kind of spelling people second-guess.
- #79,273
- frequency rank, English
- 3,931
- “A” headwords
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Hard-working, diligent or regular (in attendance or work); industrious.
Corpus desk
Index EN-assiduous · assiduous · English
assiduous · rank #79,273 · 0 variants · 0 confusables
- FREQ-RARE #79,273
- LEN-LONG 9 letters
- VOW-5 5 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-MID 3,931
- PHOTO-FINISH assize
Nearest frequency peer: assize (+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 “assiduous”
Sparse band: bars invert rank so rarer forms read shorter
- archenemy
archenemy
20,738 corpus weight
- Ashbury
Ashbury
20,731 corpus weight
- assiduous
assiduous
20,728 corpus weight
- assize
assize
20,727 corpus weight
- astragalus
astragalus
20,726 corpus weight
- bailee
bailee
20,717 corpus weight
What this shows Long-tail view: where “assiduous” sits against similarly uncommon English ranks.
| Property | Value |
|---|---|
| Headword | assiduous |
| Language | English |
| Part of speech | Adjective |
| IPA | /əˈsɪdjuːəs/ |
| Letters | 9 |
| Frequency rank | #79,273 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “assiduous” in English
Rare enough to double-check
assiduous is uncommon English at frequency #79,273 among 3,931 “A” headwords, classed as anadjective, transcribed /əˈsɪdjuːəs/. Rarity is why readers land here mid-draft. Gloss: "Hard-working, diligent or regular (in attendance or work); industrious.".
Our edit-distance generator produced no likely misspellings for assiduous, and the word's spelling is regular enough that our generator found nothing worth flagging. It is not paired with a close-neighbour confusable in our dataset, which tends to mean the word is visually distinctive enough to stand on its own.
Etymologically, the entry records: A learned borrowing from Latin assiduus, from assidere (“to sit down to”), from ad- (“to”) + sedere (“to sit”). Compare sedulous. Cognate (via assidere) to assess. The correct English form is assiduous, spelled A-S-S-I-D-U-O-U-S.
Definition
- 1Hard-working, diligent or regular (in attendance or work); industrious.
Recorded use
Wiktionary examplesThese source excerpts show how assiduous appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
He was officious in the right time and place, quiet as a lamb when his patron seemed inclined to study or to muse, active and assiduous to assist or divert him whenever it seemed to be wished.
He died after three weeks' illness, during which Mrs. Penniman, as well as his daughter, had been assiduous at his bedside.
Etymology
A learned borrowing from Latin assiduus, from assidere (“to sit down to”), from ad- (“to”) + sedere (“to sit”). Compare sedulous. Cognate (via assidere) to assess.
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); 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
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Similar English words by spelling shape
Same letter count and similar misspelling depth for "assiduous", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 9 letters (nearest by frequency rank).