loonytarian UK /ˌluː.niˈtɛəɹi.ən/US /ˌlu.niˈtɛɹi.ən/adjective 1noun 1forms 3 adjective1 •(slang, disapproving) Related to, characteristic of, or espousing libertarianism.Of course your Ideas are a little extreme even by repug and loonytarian standards. — 1998 noun1 •(slang, disapproving) A libertarian.The only difference between Loonytarians and Communists is the class of people each party intends to oppress and which equal but opposite deep end each party want's to jump off of. — 2000 formsloonytarians · more loonytarian · most loonytarian