party to . party to {adj. phr.} Concerned with; participating in. The prosecution has been trying to show that the defendant was party to a fraud. Categories: add yours {adj. phr.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: P Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Discuss