dead set against dead set against {adj. phr.} Totally opposed to someone or something. Jack is dead set against the idea of marriage, which upsets Mary. Categories: add yours {adj. phr.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: D Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Leave my opinion