1863: Christoph Friedrich Grieb, A Dictionary of the English and German Languages, page 531, “Lachfrosch”
La<froſ<,m. laughing orridibund
1931: Norman Douglas, Summer Islands: Ischia and Ponza, page 19 (Desmond Harmsworth)
If Ischia could procure a well-regulated outlet after the manner of Stromboli, this danger might be averted and a more ridibund race of mortals evolved.
1978: Evan Esar, The Comic Encyclopedia: A Library of the Literature and History of Humor Containing Thousands of Gags, Sayings, and Stories, page 375 (Doubleday; →ISBN, 9780385062053)
The ridibund bumpkin in Yiddish jokelore is a hypergelast.