beastie boyitis Share definition Flag A person who hates all hip-hop/rap music other than the Beastie Boys has Beastie Boyitis. "My friend Garry hates all rap music apart from the Beastie Boys." "Sounds like he has Beastie boyitis" beastie boyitis by jagja April 12, 2009 0 0 Get merch Get the beastie boyitis mug. Buy Now — $32.95 See more merch