Professor Donald Cornwallis Treadway Trefusis (1921–2008) is an eccentric fictional character created by Stephen Fry. He initially appeared as an occasional contributor of "wireless essays" to Ned Sherrin's BBC Radio 4 programme Loose Ends in 1986. Trefusis was portrayed as a senior tutor at the fictional St Matthew's College and professor of philology at the University of Cambridge. He is an important character in the novel The Liar. Transcripts of the Loose Ends broadcasts were published as essays in Paperweight.