What is the longest common English word you can spell without repeating a letter?

What is the longest (perhaps not-so-common) English word that can be written using only Roman numerals?

(In reply to Answers by DJ)

For words that are valid Roman numerals using the standard form, in addition to the words you have identified
{ I (1), MI (1001), and MIX (1009) },
there are also the following words:
XI (11),  the 14th letter of the Greek alphabet,
LI (51), a traditional Chinese unit of measure [~500 meters],
DI (501), a plural of DEUS (god),
DIV (504), a foolish or stupid person,
MIL (1049), a unit of measure equal to 1/1000 of an inch or liter, and
MM (2000), an interjection expressing a pleasing taste or smell.

Edited on March 30, 2015, 9:52 am

Posted by Dej Mar on 2007-10-24 04:05:35