/ ˈvɜːmɪn; NAmE ˈvɜːrmɪn/ noun [ pl. ]
1.
wild animals or birds that destroy plants or food, or attack farm animals and birds :
On farms the fox is considered vermin and treated as such.
2.
insects that live on the bodies of animals and sometimes humans :
The room was crawling with vermin.
3.
( disapproving ) people who are very unpleasant or dangerous to society
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WORD ORIGIN
Middle English (originally denoting animals such as reptiles and snakes): from Old French , based on Latin vermis worm.