2. Foolish, deceitful, or boastful language, worthless, deceptive, or insincere. Pretentious, insolent talk or behavior. i.e. bullshit. Or one who engages in such behaviors i.e. a poser.
Often used in certain fixed constructions e.g.
To pull a Van Dusen, to drop a Van Dusen.
2. Did you hear that guy who wouldn't shut up about St. Augustine? Jeez, what a Van Dusen.