My husband and I are both classical music aficionados, and we enjoy trying to identify composers of pieces we hear on the radio. One evening, while we were listening to a somewhat modern-sounding yet fairly tonal work, my husband commented, "It sounds kind of Coplandesque," referring, of course, to the great American composer Aaron Copland. I agreed, but thought the adjective ought to be "Coplandian."
Which is it? A Google search on both terms revealed pretty equal frequencies of both. In the most recent issue of Newsweek, two different articles employ the descriptors "Clintonesque" and "Clintonian." I could also imagine the somewhat lower-register "Clintonish" and "Clinton-like." There are subtle differerences between the suffixes; the American Heritage Dictionary defines "-esque" as "In the manner of; resembling: Lincolnesque" but "-ian" as "Of, relating to, or resembling: Bostonian."
Young Calvin, of the comic strip Calvin and Hobbes, describes ever so succinctly this practice of forcing words into different parts of speech: "Verbing weirds language." So does adjectiving.