dated slang One or more police officers or the police in general. (Though the term is gendered, it does not necessarily refer to a male officer.) The guy was trying to break into the store in broad daylight, and he was completely unfazed when Johnny-be-good rolled up to arrest him. The company's CEO was taken away by Johnny-be-good on charges of embezzlement and money laundering.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
n. a police officer. Here comes Johnny-be-good, so be good.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.