Portmanteau of "modernist" and "afro", i.e. an afro hairstyle worn by modernist thinkers, or more loosely, early-20th century writers, such as poet Ezra Pound, playwright George S. Kaufman, The New Yorker founder Harold Ross, and playwright August Strindberg.
George S. Kaufman had some crazy jokes." "And some crazy hair. That guy had a mofro.