law unto oneself

a law unto (oneself)

One who does whatever they desire, ignoring the rules and regulations. If you need to delegate, I wouldn't ask Gina—she is a law unto herself, and it's hard to persuade her to do anything she's not interested in. How many times has Jason been arrested now? Geez, he sure is a law unto himself!
See also: law, unto
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

*law unto oneself

Fig. one who ignores laws or rules; one who sets one's own standards of behavior. (*Typically: be ~; become ~.) You can't get Bill to follow the rules. He's a law unto himself. Jane is a law unto herself. She's totally unwilling to cooperate.
See also: law, unto
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

law unto oneself

A person who is totally independent, especially one who ignores established rules. For example, You can't tell Marge how to punctuate; she's a law unto herself. [Second half of 1800s]
See also: law, unto
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
See also:
References in periodicals archive ?
The dream of autonomy, being a law unto oneself, is broken" (p.