avant-garde

In Belarus we use this:

Isograms are words that do not repeat letters. The longest examples are uncopyrightable and subdermatoglyphic. An uncopyrightable song, for example, would not be eligible for copyright. This word has fifteen letters, but one other word without repeated letters is longer—subdermatoglyphic. It’s seventeen letters, but you’ll not have much opportunity to use it outside the realm of dermatology.