monster vs anomaly

monster and anomaly both are nouns.

Word	Noun	Adjective	Verb	Adverb
monster	Yes	No	No	No
anomaly	Yes	No	No	No

As nouns, anomaly is a hypernym of monster; that is, anomaly is a word with a broader meaning than monster:

Other hypernyms of monster include unusual person.

monster (noun)	anomaly (noun)
(medicine) a grossly malformed and usually nonviable fetus	(astronomy) position of a planet as defined by its angular distance from its perihelion (as observed from the sun)
a cruel wicked and inhuman person	a person who is unusual
a person or animal that is markedly unusual or deformed	deviation from the normal or common order or form or rule
an imaginary creature usually having various human and animal parts
someone that is abnormally large and powerful