freak vs monster

freak and monster both are nouns.

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

As nouns, freak and monster are synonyms defined as:

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

Other synonyms of freak include lusus naturae, monstrosity.

freak (noun)	monster (noun)
a person or animal that is markedly unusual or deformed	(medicine) a grossly malformed and usually nonviable fetus
someone who is so ardently devoted to something that it resembles an addiction	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

freak (verb)	monster (verb)
lose one's nerve