behind someone's back
Proposed by a contributor, not yet supported by evidence.
Meaning · English
to do something secretly without someone's knowledge
Nghĩa · Tiếng Việt
Làm điều gì đó bí mật mà không có kiến thức của ai đó
Machine-translated — suggest a fix
Literally: physically at the rear of a person
Where it’s used:
Used
Widespread English
Examples
You think I don't have the right to know what's being said behind my back?
What they offer out front is something completely different from what they're really doing behind their backs or up their sleeves.
British National Corpus sentence via the MAGPIE corpus (CC BY 4.0, retrieved 2026-07-30)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-30; pending editor spot-check.
Common questions
What does “behind someone's back” mean?
to do something secretly without someone's knowledge Literally: physically at the rear of a person
Is “behind someone's back” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.