show someone who's boss
show (one) who's boss
To demonstrate authority or dominance over one so that it is clearly recognized, especially by means of defeat or some form of subjugation. You can't keep letting your employees walk all over you like that. You need to show them who's boss. You saw what their players said about us on Twitter. Let's go out there and show them who's boss in this conference.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
show someone who's bossmake it clear that it is yourself who is in charge.
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