back·slide /ˌbækˈslaɪd $ ˈbækslaɪd/ verb (past tensepst and past participlepp backslid /-slɪd/) [intransitiveI] 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 [countableC]