vermin vs varmint

vermin and varmint both are nouns.

Word	Noun	Adjective	Verb	Adverb
vermin	Yes	No	No	No
varmint	Yes	No	No	No

As nouns, vermin and varmint are synonyms defined as:

vermin (noun)	varmint (noun)
any of various small animals or insects that are pests; e.g. cockroaches or rats	any usually predatory wild animal considered undesirable; e.g., coyote
an irritating or obnoxious person	an irritating or obnoxious person