back door
noun
1- the door or entrance at the back of a building（建筑物的）后门。
1.1
- as modifier achieved by using indirect or dishonest means开后门的; 不正当的：
a back-door tax increase.
不正当的税收增长。
1.2
- a feature or defect of a computer system that allows surreptitious unauthorized access to data（计算机系统中的）后门。
短语
by（或through）the back door
- using indirect or dishonest means to achieve an objective开后门; 用不正当途径。