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

The researchers also found that inflammation pushes cancer cells into a more immature, neuron-like state, which enhances their ability to spread and is linked to relapse.

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

Many patients relapse after treatment and require additional lines of therapy, Gilead said.

From Barron's • Feb. 23, 2026

As Garfield's progress slowed, and especially after his distressing relapse, the doctors began to consider removing the bullet in order to save his life.

From "Ambushed!" by Gail Jarrow

Related Words

• recidivism
• recurrence
• regression
• worsening