backslide

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++back·slide /ˌbækˈslaɪd $ ˈbækslaɪd/ verb (past tense and past participle backslid /-slɪd/) [intransitive]  BAD BEHAVIOUR OR ACTIONSto start doing the bad things that you used to do, after having improved your behaviour 故态复萌，退步 —backslider noun [countable]→ See Verb table

Examples from the Corpus

backslide• Many of the patients backslide into drug and alcohol abuse.• It would have looked, moreover, as though the Government were backsliding, so a swift change of tack was ordained.

back·slide verbChineseSyllable  

to things to do, the start bad that you used doing Corpus

backslide
back‧slide /ˌbækˈslaɪd $ ˈbækslaɪd/ verb (past tense and past participle backslid /-slɪd/) [intransitive]
to start doing the bad things that you used to do, after having improved your behaviour
—backslider noun [countable]