Vermin are small animals or insects that spread disease and damage. Kill the vermin, vermin control, treat them as vermin.
It is a judgement rather than a category — rats, mice and foxes are vermin when they are in your building and wildlife when they are not. Applied to people it is among the ugliest words in the language, and has been used to prepare the ground for atrocity.
1nounverminSmall animals or insects that spread disease and damage.
“The farmer set traps to keep rats and other vermin out of the grain store.”
vermin is a pest.
You already know worm. Vermin is Latin vermis, a worm, turned into a word for the whole crawling crowd of them — everything that gets into the grain and the walls.
hooks ontoworm
Old French vermine comes from Latin vermis, a worm, through a collective form meaning worms and grubs.
Latin
vermis — worm
Vulgar Latin
*verminum — vermin
Old French
vermine
Middle English
vermyn
English, today
vermin
From Middle English vermyn, vermyne, from Old French vermine, from Vulgar Latin verminum (“vermin”), collective noun formed from Latin vermis (“worm”). Compare vermiculate and vermivorous. See also worm.
Etymology from Wiktionary, CC BY-SA