relapse

Noun

• a failure to maintain a higher state

Verb

• go back to bad behavior
  • Those who recidivate are often minor criminals
    

• deteriorate in health
  • he relapsed
    

Related words

• Synonyms: 
  backsliding , lapse , lapsing , relapsing , reversion , reverting , recidivate , regress , retrogress , fall back , get worse
• Antonyms: 
  get well , get over , bounce back