modafinil
"modafinil" is a 9-letter English headword indexed on PlainSpell.
The verdict
“modafinil” is uncommon English (frequency #70,912 among 36,575 “M” headwords), classed as a noun. The kind of spelling people second-guess.
- #70,912
- frequency rank, English
- 36,575
- “M” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A stimulant often used in the treatment of various sleep disorders, having the chemical formula C₁₅H₁₅NO₂S
| Property | Value |
|---|---|
| Headword | modafinil |
| Language | English |
| Part of speech | Noun |
| Letters | 9 |
| Frequency rank | #70,912 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “modafinil” sits in English frequency
Rare enough to double-check
modafinil is uncommon English at frequency #70,912 among 36,575 “M” headwords, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "A stimulant often used in the treatment of various sleep disorders, having the chemical formula C₁₅H₁₅NO₂S".
The misspelling generator found no plausible variants for modafinil, a sign its spelling follows regular English conventions. Our dataset records no confusable match here, since its spelling is unusual enough that it doesn't cluster with a lookalike.
This headword's origin isn't recorded in our source data, so any spelling logic here comes from how the word's sounds map to letters, not a documented origin story. The correct English form is modafinil, spelled M-O-D-A-F-I-N-I-L.
Definition
- 1A stimulant often used in the treatment of various sleep disorders, having the chemical formula C₁₅H₁₅NO₂S
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 “modafinil”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is M-O-D-A-F-I-N-I-L - every other letter order is a misspelling in standard orthography.
- Browse more English words and confusable pairs in the same reference. English words
Other uncommon English words near this rank
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.