Public Enemy Number One

or Public Enemy Number 1, Public Enemy No. 1


noun

(not in official use) a criminal at the top of the FBI's list of the ten most wanted criminals.
a major menace to public safety, health, etc.: Cancer is Public Enemy Number One.

Origin of Public Enemy Number One

An Americanism dating back to 1930–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019