relapse

American  

[ri-laps, ri-laps, ree-laps] / rɪˈlæps, rɪˈlæps, ˈri læps /

verb (used without object)

relapsed, relapsing

1. to fall or slip back into a former state, practice, etc..

   to relapse into silence.

2. to fall back into illness after convalescence or apparent recovery.

3. to fall back into vice, wrongdoing, or error; backslide.

   to relapse into heresy.

   Synonyms:

   lapse, revert, regress

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noun

1. an act or instance of relapsing.

2. a return of a disease or illness after partial recovery from it.

relapse British  

verb

1. to lapse back into a former state or condition, esp one involving bad habits

2. to become ill again after apparent recovery

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noun

1. the act or an instance of relapsing

2. the return of ill health after an apparent or partial recovery

Other Word Forms

• relapsable adjective
• relapser noun
• unrelapsing adjective

Etymology

Origin of relapse

First recorded in 1400–50; (for the verb) late Middle English, from Latin relāpsus “slid back,” past participle of relābī “to slide back, revert,” from re- re- + lābī “to fall, slide, make a mistake”; noun derivative of the verb

Example Sentences

Most patients experience a relapse, followed by rapid disease progression.

From Science Daily • Mar. 25, 2026

"I was meant to return to Leicester but they didn't want me back in because they didn't want a relapse on their books. So I trained alone for a week and then went into Charlton."

From BBC • Feb. 28, 2026

The stories in Lauren Groff’s third collection, “Brawler,” largely feature people who’ve hit crisis points in their lives: the abusive partner, the natural disaster, the relapse, the deathbed.

From Los Angeles Times • Feb. 26, 2026

The intismeran autogene vaccine, combined with Keytruda, reduced the risk of relapse or death for melanoma patients in a Phase 2b trial.

From Barron's • Jan. 22, 2026

He’s suffered a relapse, I thought; he is back in his delirium.

From "Z for Zachariah" by Robert C. O’Brien

Related Words

• recidivism
• recurrence
• regression
• worsening