abderian [æbˈdɛərɪən] a.
1.) Given to laughter; inclined to foolish or incessant merriment (Webster's Revised Unabridged Dictionary).
Etymology: Latin, from Abdera, adoption of Greek Άβδηρα, a town in Thrace where Democritus, the "laughing philosopher", was a native.
"Heidelberg: Then let me bruise it in upon your brains that you should have the interest of my children as much at heart as my own interests, sir. Abderian ape! What are you grinning at?
Markus: Ha, ha, ha, ha, ho, ho, hu, hu, ha, ha!
Heidelberg: Baboon! hold down your risibility or he will trot you into trouble, sir" (Hernarne: a Comedy, William B. Felts, 1891).