Cách sử dụng
The expression "by/through the back door" means to do something secretly or sneakily, often with deceit or dishonesty. It can also refer to getting something done without going through the proper channels, using shortcuts or loopholes. You might hear someone use this expression if they are talking about someone who got a job without going through a formal interview, or if someone received a promotion without deserving it. It suggests that the person did something sneaky or dishonest to achieve their goal instead of following the proper procedure.