When cancer you thought was cured comes back, the return of the cancer is an example of a relapse.
- To fall back into illness.
- To fall back into bad habits, wrongdoing, etc.; backslide.
When an alcoholic has been sober for two months and he slips and has a drink, this is an example of a situation where he relapses.
When your cancer was cured but it came back a year later, this is an example of a situation where you relapse.
Alas! from what high hope to what relapse / Unlooked for are we fallen! "” Milton.
Origin of relapse
- Middle English relapsen to forswear from Latin relābī relāps- to fall back gradually re- re- lābī to slide
From American Heritage Dictionary of the English Language, 5th Edition