Do something behind your back
Meaning: do (harmful) things secretively
Example: I hate people who do things behind my back. He did it behind my back again.
Π‘Π΅ΡΠΈΠ°Π»Ρ ΠΈ ΡΠΈΠ»ΡΠΌΡ Π½Π° Π°Π½Π³Π»ΠΈΠΉΡΠΊΠΎΠΌ Ρ ΡΡΠ±ΡΠΈΡΡΠ°ΠΌΠΈ. +1 ΠΠ΅ΡΡΡ Π² ΠΏΠΎΠ΄Π°ΡΠΎΠΊ π
Example: I hate people who do things behind my back. He did it behind my back again.