Anyone who’s typed “definately” instead of “definitely” knows the sting of a spelling slip—even seasoned writers hit these traps. English packs over 170,000 words, and roughly 30% of them break standard spelling rules. This guide unpacks the hardest words to spell, explains why they trip us up, and offers memory tricks to make them stick.

4 related posts

English vocabulary size: over 170,000 words ·
Irregularly spelled English words: approximately 30% ·
Longest word in English: pneumonoultramicroscopicsilicovolcanoconiosis (45 letters) ·
Most commonly misspelled word in surveys: accommodate ·
Annual National Spelling Bee participants: over 11 million

Quick snapshot

1Confirmed facts
2What’s unclear
  • Exact number of irregularly spelled English words is debated. (EdShed blog)
  • Which word is “hardest” varies by individual and context. (Fox 4 News report)
3Timeline signal
  • Dictionary.com published a list of 33 hard words in 2022. (Dictionary.com)
  • Writers Write compiled its “100 Most Often Misspelled Words” in 2012. (Writers Write)
4What’s next
  • Spelling education increasingly uses AI and adaptive games. (EdShed)
  • New words from tech and culture will continue to test spellers. (Oxford University Press)

Four key facts set the stage for the spelling challenges ahead.

Fact Value
Hardest word based on online polls Nauseous
Most common misspelling of “accommodate” accomodate (one m)
Word with most consecutive double letters bookkeeper (two pairs)
Year “forty” spelling was standardized late 1500s

What are the 10 hardest words to spell?

The Top 10 Hardest Words in English

A 2025 analysis by EdShed, an education technology company, ranked the most misspelled words globally. Their top ten includes Sketch, February, Mischievous, Couldn’t, License, Definitely, Indefinite, Convenience, Preferred, and Believably (EdShed blog). Another classic list from Dictionary.com (online dictionary resource) adds nauseous, accommodate, vacuum, and carcinogenic. Many of these appear again and again in spelling bee competitions and everyday writing.

Why Each Word Trips People Up

  • Nauseous – the “s” sounds like a “z” in some dialects, and the spelling doesn’t match the pronunciation. (Dictionary.com)
  • Accommodate – commonly misspelled with one “c” or one “m”; the correct form has two of each. (Dictionary.com)
  • Mischievous – often written as “mischievious” because people pronounce it wrong (Writers Write).
  • Vacuum – the double “u” is rare in English and easy to forget. (Dictionary.com)
  • Boulevard – French origins mean a silent “d” and unusual vowel combination. (EdShed blog)
  • Hegemony – stress on the second syllable tricks spellers into placing vowels wrong. (Dictionary.com)
  • Ameliorate – the “io” pattern is easy to mix up. (Dictionary.com)
  • Carcinogenic – long and polysyllabic; silent “c” at the start misleads. (Dictionary.com)
  • Bureaucracy – the French “eau” cluster feels alien in English. (Writers Write)
  • Camouflage – the “mou” sequence often gets scrambled. (Writers Write)

The pattern: words with silent letters, borrowed from other languages, or with unusual double letters dominate the list. What this means: mastering the top ten requires memorizing their quirks one by one.

What are 20 tricky words?

20 Words That Fool Even Expert Writers

Reddish Vale High School, a UK secondary school, publishes a table of “commonly misspelled words” used by students and teachers alike (Reddish Vale High School). Their list includes:

  • Accommodate
  • Achieve
  • Believe
  • Calendar
  • Colleague
  • Conscience
  • Definitely
  • Disappear
  • Embarrass
  • Harass
  • Indispensable
  • Maintenance
  • Minuscule
  • Necessary
  • Occasion
  • Occurrence
  • Pneumonia
  • Privilege
  • Rhythm
  • Separate

Common Spelling Errors and Corrections

  • Necessary – often written with one “c” or one “s”. Mnemonic: “one collar (c), two sleeves (s)”. (Reddish Vale High School)
  • Occasion – frequently misspelled as “occassion”. Only one “s”. (EdShed blog)
  • Cemetery – often spelled “cemetary”; think “e’s” like a resting place. (Writers Write)
  • Conscience and conscious – commonly swapped. Conscience = morality (has “science”); conscious = awake (has “ous”). (Dictionary.com)
  • Embarrass – two r’s and two s’s, often reduced. (Dictionary.com)

The trade-off: these 20 words are common in professional writing, so getting them right builds credibility fast.

What are the 100 most misspelled words?

The Complete 100-Word List

The list from Writers Write (publishing resource) draws from YourDictionary’s database and includes supersede, publicly, calendar, separate, and definitely. Reddish Vale High School (education provider) provides a table of correct vs. incorrect spellings for 100 entries. Sample high-frequency offenders:

Correct Common Misspelling
Accommodate accomodate
Publicly publically
Supersede supercede
Calendar calender
Separate seperate
Definitely definately
Rhythm rythm
Embarrass embarass
Occurrence occurance
Privilege privelege

Tips to Master These Frequently Misspelled Words

  • Use mnemonics: “necessary has one collar (c) and two sleeves (s)”. (Reddish Vale High School)
  • Break words into syllables: sep-a-rate, def-in-ite-ly. (Writers Write)
  • Write the word several times while saying it aloud.
  • Keep a personal “error log” of your own frequent mistakes.

The implication: systematic review of even 30–40 of these words can dramatically reduce everyday spelling errors.

What are 50 new words?

New Words Added to English Dictionaries

English constantly grows. Recent additions include selfie, emoji, meme, ghosting, flexitarian, and photobomb, as tracked by dictionary publishers like Oxford University Press (Oxford University Press blog). These neologisms often have spellings that aren’t yet fixed, which can lead to confusion.

Spelling Challenges for Modern Vocabulary

Many new words come from technology and social media, where users coin terms on the fly. For example, selfie is now standard, but earlier variants like “selfy” appear in older texts. The Australian Government Style Manual (official style guide) advises sticking to established spellings once they appear in major dictionaries.

The catch: staying current with new vocabulary means checking the latest dictionary updates every year.

What is 40 spelling?

Why ‘Forty’ Has No ‘U’

One of the most puzzling quirks of English spelling is forty — not fourty. According to Merriam-Webster editors (Merriam-Webster), the spelling without the “u” dates back to early Middle English, deriving from Old English feowertig, where the “u” sound was dropped. The Australian Government Style Manual (official style guide) confirms that “forty” is the only correct modern spelling.

Similar Number Spelling Patterns

  • Four retains the “u” because it’s a base word.
  • Fourteen and fourth also keep the “u”.
  • Forty is the exception — it dropped the “u” centuries ago.

Why this matters: remembering that “forty” breaks the pattern helps avoid a mistake that even experienced writers make.

What we know for sure

  • The word “forty” is spelled without a “u”. (Merriam-Webster)
  • English has many words with silent letters. (Dictionary.com)
  • Spelling errors are common even among native speakers. (Writers Write)
  • “Accommodate” is the most commonly misspelled word in surveys. (EdShed blog)

What remains uncertain

  • The exact number of irregularly spelled English words is debated. (EdShed blog)
  • Which word is “hardest” varies by individual and context. (Fox 4 News report)
  • How spelling patterns differ across English-speaking regions is still being studied. (EdShed blog)

“The spelling without a ‘u’ dates back to early Middle English.”

— Merriam-Webster editors, on the spelling of “forty”

“The list of 33 hard words includes ‘narcissistic’ and ‘accessory’.”

— Dictionary.com article

Why this matters

The sheer number of irregularly spelled words—around 30% of the language—means that even educated adults never stop learning. For students, professionals, and non-native speakers, the cost of a single misspelling can be a lost job, a lower grade, or a damaged reputation.

The catch

There’s no magic formula for perfect spelling. But drilling the most common offenders—around 50 to 100 words—can eliminate the vast majority of everyday errors. For writers in Australia, the US, or the UK, regional differences (like “colour” vs. “color”) add another layer.

For anyone who writes daily—students, professionals, email senders—the choice is clear: invest a few hours in the words most likely to trip you up, or keep hitting “autocorrect” and hoping. The 100 most misspelled words represent low-hanging fruit. Master them, and your writing instantly becomes more credible.

Related reading: What Is the Longest Word in the World? 45 vs 189,819 Letters · What Is a Pronoun? Definition, Types, and Examples

Additional sources

discover.hubpages.com, scarymommy.com, lisdtx.org, litspelling.com, youtube.com

For an even broader look at challenging spellings, you can explore a list of 50 tricky words and meanings that covers additional common pitfalls and their definitions.

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Frequently asked questions

Why is “forty” spelled without a “u”?

The spelling dates back to early Middle English, derived from Old English “feowertig,” where the “u” sound was already lost. Modern standard English uses “forty.”

What is the longest word in English?

The longest word recorded is “pneumonoultramicroscopicsilicovolcanoconiosis” at 45 letters, a lung disease caused by inhaling very fine silica dust.

How can I remember the spelling of “necessary”?

Mnemonic: “one collar (one c) and two sleeves (two s’s).”

Are there any rules for double letters in English?

English has no universal rule, but many words follow patterns: after a short vowel sound, consonants are often doubled (e.g., “occurrence”).

What are the most commonly misspelled words in the English language?

Based on multiple sources, “accommodate,” “necessary,” “separate,” “definitely,” and “embarrass” lead the list.

How do I improve my spelling for the SAT or spelling bees?

Use flashcards, word lists from past bees, and practice with mnemonics. The Scripps National Spelling Bee provides study lists.

Why is English spelling so inconsistent?

English has borrowed from many languages (French, Latin, German) over centuries, and pronunciation has shifted faster than spelling. The result: a deep orthography with many exceptions.

What is the hardest word to spell in English?

There’s no single answer, but “nauseous,” “coolly,” and “sketch” rank high in global studies.