lunatic vs madcap

lunatic and madcap both are nouns.

Word	Noun	Adjective	Verb	Adverb
lunatic	Yes	Yes	No	No
madcap	Yes	Yes	No	No

As nouns, lunatic and madcap are synonyms defined as:

Other synonyms of lunatic include daredevil, harum-scarum, hothead, swashbuckler.

lunatic (noun)	madcap (noun)
an insane person	a reckless impetuous irresponsible person
a reckless impetuous irresponsible person

lunatic (adjective)	madcap (adjective)
insane and believed to be affected by the phases of the moon	characterized by undue haste and lack of thought or deliberation