「走後門」字面意思是「enter by the back door」，比喻不是通過正當途徑，而是通過內部關係謀取通融或利益（secure advantages through pull or influence），帶有貶義。
「開後門（open a back door），則比喻當權者以權謀私，濫用職權為他人提供方便（abuse one's powers to secure advantages for others）。
例句：
她找工作走後門。
Someone is pulling strings to get a job for her.
這些年買名煙名酒用不著走後門了。
These years back-door dealings are not needed to buy cigarettes and wines of brand names.
他能走後門是因為他父親是局長。
His father is the head of a bureau, so he got in through the back door.