1200–50; Middle English thwert (adv.) < Old Norse thvert across, neuter of thverr transverse; cognate with Old English thweorh crooked, cross, Gothic thwairhs cross, angry

1. hinder, obstruct. Thwart, frustrate, baffle imply preventing one, more or less completely, from accomplishing a purpose. Thwart and frustrate apply to purposes, actions, plans, etc., baffle, to the psychological state of the person thwarted. Thwart suggests stopping one by opposing, blocking, or in some way running counter to one's efforts. Frustrate implies rendering all attempts or efforts useless or ineffectual, so that nothing ever comes of them. Baffle suggests causing defeat by confusing, puzzling, or perplexing, so that a situation seems too hard a problem to understand or solve.