A back lane or byway behind houses or main streets; a narrow side street often used as a shortcut and typically less trafficked.
帰り道はいつも裏道を通って渋滞を避ける。
I always take the back street on the way home to avoid traffic jams.
配達の人は裏道を使って素早く商品を届けた。
The delivery person used a back lane to deliver the goods quickly.
夜は人通りの少ない裏道を避けたほうが安全だ。
It's safer to avoid back lanes with little foot traffic at night.
Used figuratively for dishonest or illicit means — backdoor dealings or unfair methods not following official procedures.
彼は仕事を取るために裏道を使ったと噂されている。
There are rumors he used backdoor methods to get the job.
政府と業者の裏道の関係が問題になった。
The backdoor relationship between the government and contractors became an issue.
裏道に頼るやり方は長続きしない。
Methods that rely on backdoor deals don't last long.