monstrosity vs monster

monstrosity and monster both are nouns.

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

As nouns, monstrosity and monster are synonyms defined as:

monstrosity and monster: a person or animal that is markedly unusual or deformed

Other synonyms of monstrosity include freak, lusus naturae.

monstrosity (noun)	monster (noun)
something hideous or frightful	(medicine) a grossly malformed and usually nonviable fetus
a person or animal that is markedly unusual or deformed	a cruel wicked and inhuman person
	a person or animal that is markedly unusual or deformed
	an imaginary creature usually having various human and animal parts
	someone that is abnormally large and powerful