varmint vs beast

varmint and beast both are nouns.

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

As nouns, beast is a hypernym of varmint; that is, beast is a word with a broader meaning than varmint:

varmint: any usually predatory wild animal considered undesirable; e.g., coyote
beast: a living organism characterized by voluntary movement

Other hypernyms of varmint include animal, animate being, brute, creature, fauna.

varmint (noun)	beast (noun)
any usually predatory wild animal considered undesirable; e.g., coyote	a living organism characterized by voluntary movement
an irritating or obnoxious person	a cruelly rapacious person