fanatical vs overzealous

fanatical and overzealous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
fanatical	No	Yes	No	No
overzealous	No	Yes	No	No

As adjectives, fanatical and overzealous are synonyms defined as:

fanatical and overzealous: marked by excessive enthusiasm for and intense devotion to a cause or idea

Other synonyms of fanatical include fanatic, rabid.

fanatical (adjective)	overzealous (adjective)
marked by excessive enthusiasm for and intense devotion to a cause or idea	marked by excessive enthusiasm for and intense devotion to a cause or idea