The Longest Words in English: Get Ready to Challenge Yourself!

The longest word in the English language is “pneumonoultramicroscopicsilicovolcanoconiosis.”

Try saying that quickly five times!

In this post we’ll explore some of the longest words in English, plus teach you how to break them down so that you can pronounce them easily.


Longest Word in English: Pneumonoultramicroscopicsilicovolcanoconiosis

Letters: 45

Definition (noun): Lung disease caused by breathing in dust or volcanic ash

The patient is experiencing signs of pneumonoultramicroscopicsilicovolcanoconiosis after hiking near the site of a volcanic eruption.

This is the longest word that exists in the English language. As with other long words, you should be patient and break it down into its individual components.

As you can see below, knowing the parts of this word will be especially helpful for anyone studying English in an academic, scientific or medical environment.

Essential word parts: Pneumo- (lung), microscopic- (small), coni- (particles) and a suffix: -osis (often indicates a disease).

More Long Words in English

longest word in english

We will show you the essential parts of these long words that can help you learn the word itself and other English words. We will specifically note common English prefixes and suffixes to pay attention to.


Letters: 189,819

Definition (noun): Chemical composition of “titin,” which is the largest known protein in the body  

This word has taken some people around 2-3.5 hours to pronounce! Amazing, isn’t it? It’s not, however, considered the longest word in English—because it’s not in a dictionary. 

Essential word parts: Amino acid residues that make up the protein. These include methionine, threonine, glutamine, alanine, and isoleucine.


Letters: 29

Definition (noun): Deciding that something has no value

Since my wallet was becoming so huge, I took a few minutes for some floccinaucinihilipilification of all the old cards I was keeping in there.

This is one of those complex words that seems made up. It was formed from various Latin words and can still be confusing to understand after breaking it down.

Essential word part: Nihili- (nothing)


Letters: 19

Definition (noun): Impossible to understand

The incomprehensibility of the word made people question its meaning.

This word has common prefixes and suffixes that you will see in many other English words. Plus, you may already be familiar with more basic forms of this word, such as incomprehensible (adjective — impossible to understand)

Essential word parts: include a prefix in- (not), a root word prehend (from the Latin for “grasp”), and a suffix: –ity (suffix used to form a noun out of an adjective).


Letters: 13

Definition (adjective): Secret, stealthy

The robbers were surreptitious as they stole the jewels.

This word is used fairly regularly among native English speakers. It is one of the less complex long English words.

Essential word part: Prefix: sur- (under, below)


Letters: 20

Definition (adverb): Not typical

The star basketball player uncharacteristically missed the game-winning shot.

Here is another fairly standard word that helps you practice both a common prefix and suffix.

Essential word parts: Prefix: un- (not) and a suffix: -ly (used to form an adjective)


Letters: 34

Definition (adjective): Especially wonderful

The sun is shining and all is right in the world. It is a supercalifragilisticexpialidocious day.

This is a made-up word that native English speakers recognize from the classic 1964 “Mary Poppins” movie (although a version of this word was invented even earlier).

Essential word parts: Cali- (beauty).


Letters: 17

Definition (adjective): Pertaining to the layer of the skin beneath the fingertips

The subdermatoglyphic state of everyone’s fingerprints are different.

This word is extremely rare, and may be more interesting to linguists than to medical professionals. That is because it is a very long isogram, or a word that does not repeat any letters.

Essential word parts: Prefix: sub- (under, below — similar to “sur-“), derma- (skin) and a suffix: -ic (used to form an adjective).


Letters: 11

Definition (adjective): Self-restraining

You never have trouble sticking to your diet. You are so abstentious!

You will more commonly hear abstain, the verb form of this word. Abstain means to avoid or restrain yourself from something, like alcohol, online-shopping, food, etc.

Essential word parts: Suffix: -ious (used to form an adjective).


Letters: 15

Definition (adjective): Not able to copyright a piece of artwork. If something is uncopyrightable, one person cannot prevent others from copying or distributing the art.

The idea was not original, so it was unfortunately uncopyrightable.

Un- and -able are common word parts. Try to memorize these and look for them in other English words.

Essential word parts: Prefix: un- (not) and a suffix: -able (ability).


Letters: 35

Definition (noun): Fear of long words

As she read this article, she realized that she had a severe case of hippopotomonstrosesquipedaliophobia.

This may be how you are feeling right now.

Essential word parts: Suffix: -phobia (fear).


Letters: 28

Definition (noun): A political philosophy opposed to the disestablishment of the Church of England.

The word was used to describe a political movement in England in the 1800s. People supporting this movement were against a plan to separate the church from the state.

There were many supporters of antidisestablishmentarianism in Wales. 

Essential word parts: Prefix: anti- (against) and dis- (opposite of), suffix: -arian (engaged in), and -ism (a belief in).


Letters: 27

Definition (noun): State of being able to achieve honors.

Dumbledore was well-known for lots of things, including being honorificabilitudinitatibus

This rare Latin word features in William Shakespeare’s play “Love’s Labour’s Lost.”

Essential word parts: A root word honorificabilitudin (the state of being honorable) and suffix: –itatibus (a state of being). 


Letters: 28

Definition (noun): A rare inherited endocrine disorder that causes abnormal growth of bones. 

She was diagnosed with pseudopseudohypoparathyroidism

Essential word parts: Pseudo-(prefix) meaning false, hypo-(prefix) meaning below. Parathyroid- (root word) small glands in our body which regulate calcium, and -ism (suffix) meaning “a belief in.”

Longest Adjectives in English

  • Unconventionally — something or someone is not following accepted standards or conventions (14 letters)
  • Uncontrollably — in a way that is too strong to be restrained or controlled (13 letters)
  • Unforgettably — in a manner that you cannot forget it (13 letters)
  • Unimaginably — in a way that’s difficult to imagine (12 letters)
  • Unmistakably — in a way that cannot be mistaken for something else (12 letters)
  • Unquestionably — in a way that cannot be doubted (13 letters)
  • Unreasonably — meaning that something is unfair or not based on good sense (12 letters)
  • Unstoppably — in a way that is unable to be stopped (11 letters)
  • Unthinkably — it means that something cannot be accepted as a possibility (11 letters)

Longest Suffixes in English

  • -ization — it creates a noun that denotes the act, process or result of an action (9 letters)
  • -iveness — it shows a quality or tendency (9 letters)
  • -fullness — it creates a noun that denotes the quality of being full or complete (9 letters)

Longest Prefixes in English

  • Inter- — meaning between, among (5 letters)
  • Trans- — meaning across or beyond (5 letters)
  • Hyper- — means excessively, beyond normal (5 letters)
  • Super- — meaning above, beyond (5 letters)
  • Ultra- — meaning extremely, beyond normal (5 letters)
  • Mega- — means very large, huge (5 letters)

Longest Verbs in English

  • Counterdemonstrate — to demonstrate in opposition to another demonstration (14 letters)
  • Decontaminate — to remove dangerous substances from something (12 letters)
  • Disenfranchise — to deprive someone of a right or privilege, especially of the right to vote (12 letters)
  • Disseminate — to spread widely or to scatter (11 letters)
  • Encapsulate — to enclose something in a capsule (11 letters)
  • Excommunicate — to expel from a church or other religious organization (12 letters)
  • Extrapolate — to infer from known facts or data (11 letters)
  • Hypothesize — to form a hypothesis or conjecture (11 letters)
  • Interrogate — to question formally or search thoroughly (11 letters)
  • Reincorporate — to incorporate again or anew (13 letters)

How to Learn the Longest Words in English

longest word in english

Firstly: Break each word down into manageable parts

While long English words can seem complex, breaking them down into parts will make learning them easier!

Each of the words we discuss in this article, we will show you the important elements including prefixes, suffixes and roots. Let’s define the parts of a word and what they represent.

  • Root word: the base form of a word
  • Prefix: an element attached to the beginning of a root word that alters its meaning
  • Suffix: an element attached to the end of a root word that alters its meaning

Secondly: Use vocabulary memory tricks

  • Put the words and word parts onto flashcards.
    Flashcards are a perfect way to study and memorize long words. The language learning program FluentU allows you to make your own multimedia flashcards which are connected to a curated library of authentic videos—including news reports, inspiring talks and music videos. 
  • Keep a running list. Track word components in a notebook. Any time you encounter a new prefix, suffix or root word, write it down in your list. This will help you keep track of the word parts you learn. You can refer to this list as you try to learn other long and complex words.


But most importantly, try to have fun with these words. Be patient and you will start pronouncing them in no time!

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