backslid
verbUK /ˌbækˈslɪd/
US /ˌbækˈslɪd/
Went back to doing something bad after trying to stop.
After promising to be good, he backslid and ate all the cookies.
RELATED WORDS
OTHER MEANINGS
2. Slipped backward on a slippery surface.
The hikers backslid down the muddy hill.
3. Returned to an old habit or belief.
She backslid into her old habit of staying up too late.
4. Declined in progress or quality.
The team backslid after losing its best player.