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)

I don't know how I missed the first part, but in addition to DJ's uncopyrighted (which is actually 13 letters, not 15) answer, there are dermatoglyphics, misconjugatedly and uncopyrightable (each 15 letters), all very common words that I use at least a hundred times a day.

Posted by Penny on 2004-07-24 13:10:55