An idiomatic expression meaning to stray from the right path—morally or socially—becoming corrupt or going wrong.
若いころ彼は悪友の影響で道を踏み外したが、今は更生している。
In his youth he went astray under the influence of bad friends, but now he has reformed.
有名人が道を踏み外すと、世間の注目を浴びる。
When a celebrity goes astray, it attracts public attention.
彼女は一時的に道を踏み外しそうになったが、家族が支えてくれた。
She almost went astray for a while, but her family supported her.