(noun) A mental illness of just being different in the way they act, talk. Such as making weird impressions, sometimes talking in a high voice, making weird faces, and just being fucking weird. Usually people with Tommytism think they are a perfectly normal member of society.
Guy 1: Dude whats wrong with you? You're making weird noises and making funny faces. Are you tommytistic or something?
Guy 2: Wtf dude? I'm perfectly fine. Only retarded people weird people have Tommytism