ETYM Cf. French relaps. Related to Relapse.
1. A sliding or falling back, especially into a former bad state; backsliding; the state of having fallen back.
2. A sliding or falling back into an illness after an apparent improvement; the state of having fallen back.
3. Worsening of a patient's condition during the course of recovery, or return of symptoms after a disease-free period.

To go back to bad behavior; SYN. lapse, recidivate, regress, retrogress, fall back.