impetuous vs madcap

impetuous is not a noun while madcap is a noun.

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

As adjectives, impetuous and madcap are synonyms defined as:

impetuous and madcap: characterized by undue haste and lack of thought or deliberation

Other synonyms of impetuous include brainish, hotheaded, impulsive, tearaway.

impetuous (noun)	madcap (noun)
	a reckless impetuous irresponsible person

impetuous (adjective)	madcap (adjective)
marked by violent force	characterized by undue haste and lack of thought or deliberation
characterized by undue haste and lack of thought or deliberation