without his/her/their permission
No deberías leer las cartas privadas de la gente sin su permiso.
You shouldn’t read people’s private letters without their permission.
El bastardo me dijo que nadie podía morir sin su permiso.
The bastard told me that no one could die without his permission.
— Diva (1981)
A decir verdad, conduje el carro de mi padre sin su permiso.
To tell the truth, I drove my father's car without his permission.