go behind someone's back

go behind (one's) back

To do something in one's absence. The phrase typically suggests wrongdoing or deceit. I can't believe you went behind my back and gossiped about me! Tom will be upset that we've gone behind his back and made the decision.
See also: back, behind, go
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

go behind someone's back

If someone goes behind your back, they do something secretly or without your permission. Leonard, you haven't been completely open with me. You think I wouldn't know when you go behind my back? They go behind our backs, they withhold information, they talk down to us like idiots. Compare with do something behind someone's back.
See also: back, behind, go
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012
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References in periodicals archive ?
The temptation to go behind someone's back in love is strong, but several faces are watching you, so think before you act.
I also know what it's like to go behind someone's back and do the same thing.
``I'm not the kind of person who would go behind someone's back. In an interview I was asked to comment on a number of band's outfits, including ours,and I commented on them.