back·slide 
/ˈbækˌslaɪd/ verb
back·slides; back·slid /ˈbækˌslaɪd/ verb /-ˌslɪd/ back·slid·ing [no obj] : to start doing something bad again after you have stopped it
▪ I was afraid of backsliding [=relapsing] into my old habits. ▪ Smokers who quit often backslide within a year.
▪ I was afraid of backsliding [=relapsing] into my old habits. ▪ Smokers who quit often backslide within a year.
— back·slid·er /ˈbækˌslaɪdɚ/ noun, plural back·slid·ers [count]
/ˈbækˌslaɪdɚ/ noun, plural back·slid·ers [count]
