Gnosticlit
Gnosticlit is a creative word that combines "gnostic" (someone who claims to have special knowledge) with "lit" (modern slang for exciting or impressive). It suggests someone who tries to come across as possessing deep knowledge or insights but is ultimately not genuine in their claims.
Despite his confident demeanor, John turned out to be nothing more than a gnosticlit, peppering his conversation with complex-sounding terms that masked his lack of true understanding.