behind (one's) back
In one's absence or without one's knowledge
behind somebody's back
if you do something behind someone's back, you do it without them knowing
behind someone's back
SECRETLY, without someone's knowledge, on the sly, slyly, sneakily, covertly, surreptitiously, furtively

[TahlilGaran] Dictionary of Contemporary English ▲

behind one's back
do something when one is absent or without one's knowledge, secretly

[TahlilGaran] Dictionary of Contemporary English ▲

behind back
behind (someone's) back
if you do something behind someone's back, you do it without them knowing, in a way which is unfair.
I don't want to talk about it behind his back.

She was accused of going behind her colleagues' backs to talk to management.

behind (your) back
when you are not present.
I often wonder what they say about me behind my back.

[TahlilGaran] English Idioms Dictionary ▲

behind back
without someone's knowledge, secretly
The man is very angry because his friend borrowed his car behind his back.

[TahlilGaran] English Idioms Dictionary ▲

behind someone's back
behind (someone's) back
if you do something behind someone's back, you do it without them knowing, in a way which is unfair.
I don't want to talk about it behind his back.

She was accused of going behind her colleagues' backs to talk to management.

behind (your) back
when you are not present.
I often wonder what they say about me behind my back.

[TahlilGaran] English Idioms Dictionary ▲

behind someone's back
without someone's knowledge, secretly
The man is very angry because his friend borrowed his car behind his back.

[TahlilGaran] English Idioms Dictionary ▲

behind one's back
do something when one is absent or without one's knowledge, secretly
I don't like people who talk behind my back.

[TahlilGaran] English Idioms Dictionary ▲

behind one's back
adv. phr. When one is absent; without one's knowledge or consent; in a dishonest way; secretly; sneakily.
Say it to his face, not behind his back.
It is not right to criticize a person behind his back.
Antonym: TO ONE'S FACE.

[TahlilGaran] English Idioms Dictionary ▲