https://www.oed.com/view/Entry/144957?rskey=Y...
3d. to avoid (also shun, etc.) like the plague, etc.: to avoid at all costs, to shun completely.
4. In extended use.
a. A person, animal, or plant whose presence, behaviour, or activities are damaging, troublesome, or (in weakened use) merely irritating; a large number of particular people, animals, or plants seen as a threat, or as a cause of trouble.
b. Something which causes constant, incessant, or overwhelming trouble or annoyance; (in weakened use) trouble, nuisance, difficulty.
Duden:
Wendungen, Redensarten, Sprichwörter
- wie die Pest (salopp: überaus intensiv, eifrig, schnell)
- wie die Pest stinken (salopp: abscheulich stinken)
- jemandem die Pest an den Hals wünschen (salopp: jemandem alles Schlechte wünschen)