Simpsonian UK /sɪmpˈsəʊ.ni.ən/US /sɪmpˈsoʊ.ni.ən/ adjective2 •Of or pertaining to The Simpsons, an American animated sitcom. •Of or relating to George Gaylord Simpson (1902–1984), US paleontologist. formsmore Simpsonian · most Simpsonian