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

Explanation

A relapse is a decline, especially of someone's health. If your grandmother survived cancer only to have it return two years later, you could say she suffered a relapse. Relapse implies that someone has recovered from an illness and slid back into a worse state, like when you are getting over a cold but then you suddenly feel bad all over again. Unwanted behavior can also be described this way; if you find yourself biting your nails again, it's a nail-biting relapse. The Latin word relabi is the root of relapse, slip back.

Example Sentences

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

From Science Daily • Mar. 25, 2026

However, while the treatment he receives is effective at preventing another relapse, he still faces problems from the damage that has already been done to his central nervous system.

From BBC • Mar. 19, 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

The news of the president's late-July relapse shocked and disappointed everyone, including his doctors.

From "Ambushed!" by Gail Jarrow

Related Words

• recidivism
• recurrence
• regression
• worsening