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What is the longest word you can come up with that is a real English word that doesn't use any individual letter more than once?

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8 Answers 8

up vote 31 down vote accepted

The usual answer (longer than nohat's discoveries, probably because the CMU dictionary doesn't contain it, but certainly a valid English word) is "UNCOPYRIGHTABLE", 15 letters.

Dermatology journals also contain the word SUBDERMATOGLYPHIC, 17 letters.

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I thought I said "uncopyrightable" somewhere. –  Arlen Beiler Aug 20 '10 at 18:44
    
What dermatology journals? There is only one I know of in which the word appears, and that is Archives of Dermatology (now JAMA Dermatology). If you know of others, I would be interested in seeing the citations. –  Psychonaut Dec 9 '14 at 14:40
    
An anonymous user suggested an edit rewriting this answer to include the word "hydropneumatics"; I'm just placing the word as a comment here. –  ShreevatsaR Mar 25 at 2:21

I wrote a quick little Perl script to scan through the CMU Pronouncing Dictionary:

#!/usr/local/bin/perl
use warnings;
use strict;
use Data::Dumper;
my @size;
while (<>) {
    my ($word) = split /  /, $_;
    next unless $word =~ m/^[A-Z]+$/;
    my @letters = split //, $word;
    my %count;
    $count{$_}++ foreach @letters;
    next if grep { $_ > 1 } values %count;
    push @{$size[length($word)]}, $word;
}
print Dumper(pop @size);

Here is the output:

$VAR1 = [
          'COPYRIGHTABLE',
          'UNPREDICTABLY',
          'WOLFENSCHMIDT'
        ];

The third is debatably an English word—it’s a name—but they are all 13 letters long.

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8  
+1 for being able to do write a quick, little Perl script like that –  Edward Tanguay Aug 13 '10 at 23:31
3  
far more fun than the real programming I'm supposed to be doing :-) –  nohat Aug 13 '10 at 23:37
    
+1 for the code –  Vincent McNabb Aug 14 '10 at 0:15
4  
+1 for resisting the temptation to write a one-liner. :-) –  ShreevatsaR Aug 14 '10 at 2:03
1  
Sounds like the StackOverflow crowd found the site. –  JohnFx Aug 14 '10 at 15:13

You can take a look at wikipedia: Isogram

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Are "misconjugatedly" and "troublemakings" really words? –  delete Aug 14 '10 at 2:33
    
@Shinto: I'm not sure with "misconjugatedly" but "troublemakings" is obviously word, at least it's in my Merriam-Webster dictionary. =) –  Anonymous Aug 14 '10 at 2:57

A quick Google search revealed a post with the following list:

  • 15,"dermatoglyphics"
  • 15,"uncopyrightable"
  • 14,"troublemakings"
  • 14,"dermatoglyphic"
  • 14,"ambidextrously"
  • 13,"documentarily"
  • 13,"consumptively"
  • 13,"copyrightable"
  • 13,"endolymphatic"
  • 13,"flowchartings"
  • 13,"hydromagnetic"
  • 13,"lycanthropies"
  • 13,"troublemaking"
  • 13,"unpredictably"
  • 13,"unproblematic"
  • 13,"subordinately"
  • 13,"metalworkings"
  • 13,"multibranched"
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A popular trivia quiz question along these lines is 'what is the longest place name in Britain that doesn't repeat any letters?' Nobody has yet found one longer than 'Bricklehampton'.

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From Fun with Words:

The longest words with no repeated letters are dermatoglyphics, misconjugatedly and uncopyrightables.

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In the dictionaries which come with FreeBSD I find:

  • 14: ambidextrously
  • 14: benzhydroxamic
  • 15: dermatoglyphics
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1  
I majored in dermatoglyphics in college. –  Chris Dwyer Sep 13 '10 at 22:06

How about:

pneumonoultramicroscopicsilicovolcanoconiosis

(And I'm not just making that up!) … I learned it as a kid, in the hopes that I could win the national spelling bee with it. ;)

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4  
It has to have each letter only once, and this fails because, for example, it has several Os. –  delete Aug 14 '10 at 7:37
22  
Agree with Shinto: It has 9 ‘o’s, 6 ‘i’s, 6 ‘c’s, 4 ‘s’s, 4 ‘n’s,… in fact it has all letters repeated except ‘v’, ‘t’ and ‘e’! Is this the maximally unacceptable answer to this question? :-) –  ShreevatsaR Aug 14 '10 at 8:04

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