1re·lapse 
/ˈri:ˌlæps/ noun
plural re·laps·es /ˈri:ˌlæps/ noun 1 : the return of an illness after a period of improvement [count] ▪ Everyone thought she was well until a sudden relapse sent her back to the hospital. [noncount] ▪ Patients who stop taking the medication have a higher risk of relapse. [=they are more likely to get sick again] 2 : a return to bad behavior that you had stopped doing [count] ▪ a drug addict who has had a relapse [noncount] ▪ a drug addict who has a history of relapse ▪ The program has a low rate of relapse. [=most people who use the program do not return to the bad behavior they had stopped doing]
