You can use backdoor to describe an action or process if you disapprove of it because you think it has been done in a secret, indirect, or dishonest way.
例句
He did the backdoor deals that allowed the government to get its budget through Parliament on time...他通过幕后交易使政府预算按时通过了议会批准。He brushed aside talk of greedy MPs voting themselves a backdoor pay rise.他没有理会贪婪的下院议员们投票为他们自己悄悄加薪的传闻。
N-SING
不正当的秘密途径；后门
If you say that someone is doing something through or by the backdoor, you disapprove of them because they are doing it in a secret, indirect, or dishonest way.
例句
Dentists claim the Government is privatising dentistry through the back door.牙医声称政府正通过暗箱操作将牙医业私有化。