assiduous
/əˈsɪdjuːəs/
"assiduous" is a 9-letter English headword indexed on PlainSpell.
The verdict
“assiduous” is an uncommon English word, ranked #79,273 in English word frequency and used as an adjective.
- #79,273
- frequency rank, English
- 9
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Hard-working, diligent or regular (in attendance or work); industrious.
| 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) |
Where “assiduous” sits in English frequency
Spelling & Dictionary Insight
The English entry for assiduous is 9 letters long, classified as an adjective, and transcribed in the International Phonetic Alphabet as /əˈsɪdjuːəs/. Corpus data places it at rank #79,273 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. The dominant gloss from Wiktionary reads: "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.
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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Using “assiduous”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is A-S-S-I-D-U-O-U-S - every other letter order is a misspelling in standard orthography.
- Say it as /əˈsɪdjuːəs/ (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.